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megatron/fused_kernels/__init__.py 0 → 100644
View file @ d3dd8642
# Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
import os
import pathlib
import subprocess
from torch.utils import cpp_extension
# Setting this param to a list has a problem of generating different
# compilation commands (with diferent order of architectures) and
# leading to recompilation of fused kernels. Set it to empty string
# to avoid recompilation and assign arch flags explicity in
# extra_cuda_cflags below
os.environ["TORCH_CUDA_ARCH_LIST"] = ""
def load(args):
# Check if cuda 11 is installed for compute capability 8.0
cc_flag = []
_, bare_metal_major, bare_metal_minor = _get_cuda_bare_metal_version(
cpp_extension.CUDA_HOME)
if int(bare_metal_major) >= 11:
cc_flag.append('-gencode')
cc_flag.append('arch=compute_80,code=sm_80')
if int(bare_metal_minor) >= 7:
cc_flag.append('-gencode')
cc_flag.append('arch=compute_90,code=sm_90')
# Build path
srcpath = pathlib.Path(__file__).parent.absolute()
buildpath = srcpath / 'build'
_create_build_dir(buildpath)
# Helper function to build the kernels.
def _cpp_extention_load_helper(name, sources, extra_cuda_flags):
return cpp_extension.load(
name=name,
sources=sources,
build_directory=buildpath,
extra_cflags=['-O3',],
extra_cuda_cflags=['-O3',
'-gencode', 'arch=compute_70,code=sm_70',
'--use_fast_math'] + extra_cuda_flags + cc_flag,
verbose=(args.rank == 0)
)
# ==============
# Fused softmax.
# ==============
if args.masked_softmax_fusion:
extra_cuda_flags = ['-U__CUDA_NO_HALF_OPERATORS__',
'-U__CUDA_NO_HALF_CONVERSIONS__',
'--expt-relaxed-constexpr',
'--expt-extended-lambda']
# Upper triangular softmax.
sources=[srcpath / 'scaled_upper_triang_masked_softmax.cpp',
srcpath / 'scaled_upper_triang_masked_softmax_cuda.cu']
scaled_upper_triang_masked_softmax_cuda = _cpp_extention_load_helper(
"scaled_upper_triang_masked_softmax_cuda",
sources, extra_cuda_flags)
# Masked softmax.
sources=[srcpath / 'scaled_masked_softmax.cpp',
srcpath / 'scaled_masked_softmax_cuda.cu']
scaled_masked_softmax_cuda = _cpp_extention_load_helper(
"scaled_masked_softmax_cuda", sources, extra_cuda_flags)
# Softmax
sources=[srcpath / 'scaled_softmax.cpp',
srcpath / 'scaled_softmax_cuda.cu']
scaled_softmax_cuda = _cpp_extention_load_helper(
"scaled_softmax_cuda", sources, extra_cuda_flags)
def _get_cuda_bare_metal_version(cuda_dir):
raw_output = subprocess.check_output([cuda_dir + "/bin/nvcc", "-V"],
universal_newlines=True)
output = raw_output.split()
release_idx = output.index("release") + 1
release = output[release_idx].split(".")
bare_metal_major = release[0]
bare_metal_minor = release[1][0]
return raw_output, bare_metal_major, bare_metal_minor
def _create_build_dir(buildpath):
try:
os.mkdir(buildpath)
except OSError:
if not os.path.isdir(buildpath):
print(f"Creation of the build directory {buildpath} failed")
megatron/fused_kernels/compat.h 0 → 100644
View file @ d3dd8642
/* Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved. */
/*This code is copied fron NVIDIA apex:
* https://github.com/NVIDIA/apex
* with minor changes. */
#ifndef TORCH_CHECK
#define TORCH_CHECK AT_CHECK
#endif
#ifdef VERSION_GE_1_3
#define DATA_PTR data_ptr
#else
#define DATA_PTR data
#endif
megatron/fused_kernels/scaled_masked_softmax.cpp 0 → 100644
View file @ d3dd8642
/* Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved. */
#include <cuda_fp16.h>
#include <torch/extension.h>
#include <vector>
namespace multihead_attn {
namespace fused_softmax {
namespace scaled_masked_softmax {
torch::Tensor fwd_cuda(
torch::Tensor const& input,
torch::Tensor const& mask,
float scale_factor);
torch::Tensor bwd_cuda(
torch::Tensor const& output_grads,
torch::Tensor const& softmax_results,
float scale_factor);
int get_batch_per_block_cuda(
int query_seq_len,
int key_seq_len,
int batches,
int attn_heads);
torch::Tensor fwd(
torch::Tensor const& input,
torch::Tensor const& mask,
float scale_factor) {
AT_ASSERTM(input.dim() == 4, "expected 4D tensor");
AT_ASSERTM((input.scalar_type() == at::ScalarType::Half) ||
(input.scalar_type() == at::ScalarType::BFloat16),
"Only fp16 and bf16 are supported");
AT_ASSERTM(mask.dim() == 4, "expected 4D tensor");
return fwd_cuda(input, mask, scale_factor);
}
torch::Tensor bwd(
torch::Tensor const& output_grads,
torch::Tensor const& softmax_results,
float scale_factor) {
AT_ASSERTM(output_grads.dim() == 4, "expected 3D tensor");
AT_ASSERTM(softmax_results.dim() == 4, "expected 3D tensor");
AT_ASSERTM((output_grads.scalar_type() == at::ScalarType::Half) ||
(output_grads.scalar_type() == at::ScalarType::BFloat16),
"Only fp16 and bf16 are supported");
AT_ASSERTM((softmax_results.scalar_type() == at::ScalarType::Half) ||
(softmax_results.scalar_type() == at::ScalarType::BFloat16),
"Only fp16 and bf16 are supported");
return bwd_cuda(output_grads, softmax_results, scale_factor);
}
int get_batch_per_block(
int query_seq_len,
int key_seq_len,
int batches,
int attn_heads) {
return get_batch_per_block_cuda(query_seq_len, key_seq_len, batches, attn_heads);
}
} // end namespace scaled_masked_softmax
} // end namespace fused_softmax
} // end namespace multihead_attn
PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
m.def("forward",
&multihead_attn::fused_softmax::scaled_masked_softmax::fwd,
"Self Multihead Attention scaled, time masked softmax -- Forward.");
m.def("backward",
&multihead_attn::fused_softmax::scaled_masked_softmax::bwd,
"Self Multihead Attention scaled, time masked softmax -- Backward.");
m.def("get_batch_per_block",
&multihead_attn::fused_softmax::scaled_masked_softmax::get_batch_per_block,
"Return Batch per block size."
);
}
megatron/fused_kernels/scaled_masked_softmax.h 0 → 100644
View file @ d3dd8642
/* Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved. */
#pragma once
#include <assert.h>
#include <cuda_fp16.h>
#include <cfloat>
#include <limits>
#include <stdint.h>
#include <cuda_fp16.h>
#include <c10/macros/Macros.h>
namespace {
template <typename Datatype, int ELEMENTS_PER_LDG>
__device__ __inline__ void copy_vector(Datatype *dst, const Datatype *src);
template <>
__device__ __inline__ void copy_vector<c10::BFloat16, 1>(c10::BFloat16 *dst, const c10::BFloat16 *src) { *dst = *src; }
template <>
__device__ __inline__ void copy_vector<c10::BFloat16, 4>(c10::BFloat16 *dst, const c10::BFloat16 *src) { *((float2*) dst) = *((float2*) src); }
template <>
__device__ __inline__ void copy_vector<c10::Half, 1>(c10::Half *dst, const c10::Half *src) { *dst = *src; }
template <>
__device__ __inline__ void copy_vector<c10::Half, 4>(c10::Half *dst, const c10::Half *src) { *((float2*) dst) = *((float2*) src); }
template <>
__device__ __inline__ void copy_vector<uint8_t, 1>(uint8_t *dst, const uint8_t *src) { *dst = *src; }
template <>
__device__ __inline__ void copy_vector<uint8_t, 4>(uint8_t *dst, const uint8_t *src) {*((half2*) dst) = *((half2*) src); }
int log2_ceil(int value) {
int log2_value = 0;
while ((1 << log2_value) < value) ++log2_value;
return log2_value;
}
template<typename T>
struct Add {
__device__ __forceinline__ T operator()(T a, T b) const {
return a + b;
}
};
template<typename T>
struct Max {
__device__ __forceinline__ T operator()(T a, T b) const {
return a < b ? b : a;
}
};
template <typename T>
__device__ __forceinline__ T WARP_SHFL_XOR_NATIVE(T value, int laneMask, int width = warpSize, unsigned int mask = 0xffffffff)
{
#if CUDA_VERSION >= 9000
return __shfl_xor_sync(mask, value, laneMask, width);
#else
return __shfl_xor(value, laneMask, width);
#endif
}
template <typename acc_t, int WARP_BATCH, int WARP_SIZE, template<typename> class ReduceOp>
__device__ __forceinline__ void warp_reduce(acc_t* sum) {
ReduceOp<acc_t> r;
#pragma unroll
for (int offset = WARP_SIZE / 2; offset > 0; offset /= 2) {
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
acc_t b = WARP_SHFL_XOR_NATIVE(sum[i], offset, WARP_SIZE);
sum[i] = r(sum[i], b);
}
}
}
/*
* Extended softmax (from native aten pytorch) with following additional features
* 1) input scaling
*/
template <typename input_t, typename output_t, typename acc_t, int log2_elements>
__global__ void scaled_softmax_warp_forward(
output_t *dst,
const input_t *src,
const acc_t scale,
int micro_batch_size,
int element_count)
{
// WARP_SIZE and WARP_BATCH must match the return values batches_per_warp and
// warp_size of method warp_softmax_forward_kernel.
constexpr int next_power_of_two = 1 << log2_elements;
constexpr int WARP_SIZE = (next_power_of_two < C10_WARP_SIZE) ? next_power_of_two : C10_WARP_SIZE;
constexpr int WARP_ITERATIONS = next_power_of_two / WARP_SIZE;
constexpr int WARP_BATCH = (next_power_of_two <= 128) ? 2 : 1;
constexpr int ELEMENTS_PER_LDG_STG = (WARP_ITERATIONS < 4) ? 1 : 4;
// blockDim/threadIdx = (WARP_SIZE, WARPS_PER_BLOCK, )
// gridDim/blockIdx = (seq_len, attn_heads, batches)
int first_batch = (blockDim.y * (blockIdx.x + gridDim.x * (blockIdx.y + gridDim.y * blockIdx.z))+ threadIdx.y) * WARP_BATCH;
// micro_batch_size might not be a multiple of WARP_BATCH. Check how
// many batches have to computed within this WARP.
int local_batches = micro_batch_size - first_batch;
if (local_batches > WARP_BATCH)
local_batches = WARP_BATCH;
// there might be multiple batches per warp. compute the index within the batch
int local_idx = threadIdx.x;
src += first_batch * element_count + ELEMENTS_PER_LDG_STG * local_idx;
dst += first_batch * element_count + ELEMENTS_PER_LDG_STG * local_idx;
// load data from global memory
acc_t elements[WARP_BATCH][WARP_ITERATIONS];
input_t temp_data[ELEMENTS_PER_LDG_STG];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
int batch_element_count = (i >= local_batches) ? 0 : element_count;
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; it+=ELEMENTS_PER_LDG_STG) {
int element_index = ELEMENTS_PER_LDG_STG * local_idx + it * WARP_SIZE;
if (element_index < batch_element_count) {
int itr_idx = i*element_count+it*WARP_SIZE;
copy_vector<input_t, ELEMENTS_PER_LDG_STG>(temp_data, src + itr_idx);
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
elements[i][it + element] = (acc_t)temp_data[element] * scale;
}
} else {
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
elements[i][it + element] = -std::numeric_limits<acc_t>::infinity();
}
}
}
}
// compute max_value
acc_t max_value[WARP_BATCH];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
max_value[i] = elements[i][0];
#pragma unroll
for (int it = 1; it < WARP_ITERATIONS; ++it) {
max_value[i] = (max_value[i] > elements[i][it]) ? max_value[i] : elements[i][it];
}
}
warp_reduce<acc_t, WARP_BATCH, WARP_SIZE, Max>(max_value);
acc_t sum[WARP_BATCH] { 0.0f };
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; ++it) {
elements[i][it] = std::exp((elements[i][it] - max_value[i]));
sum[i] += elements[i][it];
}
}
warp_reduce<acc_t, WARP_BATCH, WARP_SIZE, Add>(sum);
// store result
output_t out[ELEMENTS_PER_LDG_STG];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
if (i >= local_batches)
break;
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; it+=ELEMENTS_PER_LDG_STG) {
int element_index = ELEMENTS_PER_LDG_STG * local_idx + it * WARP_SIZE;
if (element_index < element_count) {
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
out[element] = elements[i][it + element] / sum[i];
}
copy_vector<output_t, ELEMENTS_PER_LDG_STG>(dst + i * element_count + it * WARP_SIZE, out);
} else {
break;
}
}
}
}
/*
* Extended softmax (from native aten pytorch) with following additional features
* 1) input scaling
* 2) Explicit masking
*/
template <typename input_t, typename output_t, typename acc_t, int log2_elements>
__global__ void scaled_masked_softmax_warp_forward(
output_t *dst,
const input_t *src,
const uint8_t *mask,
const acc_t scale,
int micro_batch_size,
int element_count,
int pad_batches)
{
// WARP_SIZE and WARP_BATCH must match the return values batches_per_warp and
// warp_size of method warp_softmax_forward_kernel.
constexpr int next_power_of_two = 1 << log2_elements;
constexpr int WARP_SIZE = (next_power_of_two < C10_WARP_SIZE) ? next_power_of_two : C10_WARP_SIZE;
constexpr int WARP_ITERATIONS = next_power_of_two / WARP_SIZE;
constexpr int WARP_BATCH = (next_power_of_two <= 128) ? 2 : 1;
constexpr int ELEMENTS_PER_LDG_STG = (WARP_ITERATIONS < 4) ? 1 : 4;
// blockDim/threadIdx = (WARP_SIZE, WARPS_PER_BLOCK, )
// gridDim/blockIdx = (seq_len, attn_heads, batches)
int first_batch = (blockDim.y * (blockIdx.x + gridDim.x * (blockIdx.y + gridDim.y * blockIdx.z))+ threadIdx.y) * WARP_BATCH;
int pad_first_batch = 0;
if (pad_batches != 1) { // bert style
pad_first_batch = (blockDim.y * (blockIdx.x + gridDim.x * blockIdx.z) + threadIdx.y) * WARP_BATCH;
} else { // gpt2 style
pad_first_batch = (blockDim.y * blockIdx.x + threadIdx.y) * WARP_BATCH;
}
// micro_batch_size might not be a multiple of WARP_BATCH. Check how
// many batches have to computed within this WARP.
int local_batches = micro_batch_size - first_batch;
if (local_batches > WARP_BATCH)
local_batches = WARP_BATCH;
// there might be multiple batches per warp. compute the index within the batch
int local_idx = threadIdx.x;
src += first_batch * element_count + ELEMENTS_PER_LDG_STG * local_idx;
dst += first_batch * element_count + ELEMENTS_PER_LDG_STG * local_idx;
mask += pad_first_batch * element_count + ELEMENTS_PER_LDG_STG * local_idx;
// load data from global memory
acc_t elements[WARP_BATCH][WARP_ITERATIONS];
input_t temp_data[ELEMENTS_PER_LDG_STG];
uint8_t temp_mask[ELEMENTS_PER_LDG_STG];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
int batch_element_count = (i >= local_batches) ? 0 : element_count;
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; it+=ELEMENTS_PER_LDG_STG) {
int element_index = ELEMENTS_PER_LDG_STG * local_idx + it * WARP_SIZE;
if (element_index < batch_element_count) {
int itr_idx = i*element_count+it*WARP_SIZE;
copy_vector<input_t, ELEMENTS_PER_LDG_STG>(temp_data, src + itr_idx);
copy_vector<uint8_t, ELEMENTS_PER_LDG_STG>(temp_mask, mask + itr_idx);
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
if (temp_mask[element] != 1) {
elements[i][it + element] = (acc_t)temp_data[element] * scale;
} else {
elements[i][it + element] = -10000.0;
}
}
} else {
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
elements[i][it + element] = -std::numeric_limits<acc_t>::infinity();
}
}
}
}
// compute max_value
acc_t max_value[WARP_BATCH];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
max_value[i] = elements[i][0];
#pragma unroll
for (int it = 1; it < WARP_ITERATIONS; ++it) {
max_value[i] = (max_value[i] > elements[i][it]) ? max_value[i] : elements[i][it];
}
}
warp_reduce<acc_t, WARP_BATCH, WARP_SIZE, Max>(max_value);
// compute scale value to account for full mask
acc_t scale_value[WARP_BATCH];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
scale_value[i] = (max_value[i] == -10000.0) ? 0.0 : 1.0;
}
acc_t sum[WARP_BATCH] { 0.0f };
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; ++it) {
elements[i][it] = std::exp((elements[i][it] - max_value[i]));
sum[i] += elements[i][it];
}
}
warp_reduce<acc_t, WARP_BATCH, WARP_SIZE, Add>(sum);
// store result
output_t out[ELEMENTS_PER_LDG_STG];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
if (i >= local_batches)
break;
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; it+=ELEMENTS_PER_LDG_STG) {
int element_index = ELEMENTS_PER_LDG_STG * local_idx + it * WARP_SIZE;
if (element_index < element_count) {
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
out[element] = elements[i][it + element] * scale_value[i] / sum[i];
}
copy_vector<output_t, ELEMENTS_PER_LDG_STG>(dst + i * element_count + it * WARP_SIZE, out);
} else {
break;
}
}
}
}
template <typename input_t, typename output_t, typename acc_t, int log2_elements>
__global__ void scaled_masked_softmax_warp_backward(
output_t *gradInput,
input_t *grad,
const input_t *output,
acc_t scale,
int micro_batch_size,
int element_count)
{
// WARP_SIZE and WARP_BATCH must match the return values batches_per_warp and
// warp_size of method warp_softmax_backward_kernel.
constexpr int next_power_of_two = 1 << log2_elements;
constexpr int WARP_SIZE = (next_power_of_two < C10_WARP_SIZE) ? next_power_of_two : C10_WARP_SIZE;
constexpr int WARP_ITERATIONS = next_power_of_two / WARP_SIZE;
constexpr int WARP_BATCH = (next_power_of_two <= 128) ? 2 : 1;
constexpr int ELEMENTS_PER_LDG_STG = (WARP_ITERATIONS < 4) ? 1 : 4;
// blockDim/threadIdx = (WARP_SIZE, WARPS_PER_BLOCK, )
// gridDim/blockIdx = (seq_len, attn_heads, batches)
int first_batch = (blockDim.y * blockIdx.x + threadIdx.y) * WARP_BATCH;
// micro_batch_size might not be a multiple of WARP_BATCH. Check how
// many batches have to computed within this WARP.
int local_batches = micro_batch_size - first_batch;
if (local_batches > WARP_BATCH)
local_batches = WARP_BATCH;
// there might be multiple batches per warp. compute the index within the batch
int local_idx = threadIdx.x;
// the first element to process by the current thread
int thread_offset = first_batch * element_count + ELEMENTS_PER_LDG_STG * local_idx;
grad += thread_offset;
output += thread_offset;
gradInput += thread_offset;
// load data from global memory
acc_t grad_reg[WARP_BATCH][WARP_ITERATIONS] { 0.0f };
acc_t output_reg[WARP_BATCH][WARP_ITERATIONS] { 0.0f };
input_t temp_grad[ELEMENTS_PER_LDG_STG];
input_t temp_output[ELEMENTS_PER_LDG_STG];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
int batch_element_count = (i >= local_batches) ? 0 : element_count;
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; it+=ELEMENTS_PER_LDG_STG) {
int element_index = ELEMENTS_PER_LDG_STG * local_idx + it * WARP_SIZE;
if (element_index < batch_element_count) {
copy_vector<input_t, ELEMENTS_PER_LDG_STG>(temp_grad, grad + i * element_count + it * WARP_SIZE);
copy_vector<input_t, ELEMENTS_PER_LDG_STG>(temp_output, output + i * element_count + it * WARP_SIZE);
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
output_reg[i][it + element] = (acc_t)temp_output[element];
}
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
grad_reg[i][it + element] = (acc_t)temp_grad[element] * output_reg[i][it + element];
}
}
}
}
acc_t sum[WARP_BATCH];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
sum[i] = grad_reg[i][0];
#pragma unroll
for (int it = 1; it < WARP_ITERATIONS; ++it) {
sum[i] += grad_reg[i][it];
}
}
warp_reduce<acc_t, WARP_BATCH, WARP_SIZE, Add>(sum);
// store result
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
if (i >= local_batches)
break;
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; it+=ELEMENTS_PER_LDG_STG) {
int element_index = ELEMENTS_PER_LDG_STG * local_idx + it * WARP_SIZE;
if (element_index < element_count) {
// compute gradients
output_t out[ELEMENTS_PER_LDG_STG];
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
out[element] = (output_t)(scale * (grad_reg[i][it + element] - output_reg[i][it + element] * sum[i]));
}
copy_vector<output_t, ELEMENTS_PER_LDG_STG>(gradInput + i * element_count + it * WARP_SIZE, out);
}
}
}
}
} // end of anonymous namespace
int get_batch_per_block(int query_seq_len, int key_seq_len, int batches, int attn_heads){
int log2_elements = log2_ceil(key_seq_len);
const int next_power_of_two = 1 << log2_elements;
int warp_size = (next_power_of_two < C10_WARP_SIZE) ? next_power_of_two : C10_WARP_SIZE;
int batches_per_warp = (next_power_of_two <= 128) ? 2 : 1;
constexpr int threads_per_block = 128;
int warps_per_block = (threads_per_block / warp_size);
int batches_per_block = warps_per_block * batches_per_warp;
return batches_per_block;
}
template<typename input_t, typename output_t, typename acc_t>
void dispatch_scaled_softmax_forward(
output_t *dst,
const input_t *src,
const input_t scale,
int query_seq_len,
int key_seq_len,
int batches,
int attn_heads)
{
TORCH_INTERNAL_ASSERT(key_seq_len >= 0 && key_seq_len <= 4096 );
if (key_seq_len == 0) {
return;
} else {
int log2_elements = log2_ceil(key_seq_len);
const int next_power_of_two = 1 << log2_elements;
int batch_count = batches * attn_heads * query_seq_len;
// This value must match the WARP_SIZE constexpr value computed inside softmax_warp_forward.
int warp_size = (next_power_of_two < C10_WARP_SIZE) ? next_power_of_two : C10_WARP_SIZE;
// This value must match the WARP_BATCH constexpr value computed inside softmax_warp_forward.
int batches_per_warp = (next_power_of_two <= 128) ? 2 : 1;
// use 128 threads per block to maximimize gpu utilization
constexpr int threads_per_block = 128;
int warps_per_block = (threads_per_block / warp_size);
int batches_per_block = warps_per_block * batches_per_warp;
TORCH_INTERNAL_ASSERT(query_seq_len%batches_per_block == 0);
dim3 blocks(query_seq_len/batches_per_block, attn_heads, batches);
dim3 threads(warp_size, warps_per_block, 1);
// Launch code would be more elegant if C++ supported FOR CONSTEXPR
switch (log2_elements) {
case 0: // 1
scaled_softmax_warp_forward<input_t, output_t, acc_t, 0>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, key_seq_len);
break;
case 1: // 2
scaled_softmax_warp_forward<input_t, output_t, acc_t, 1>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, key_seq_len);
break;
case 2: // 4
scaled_softmax_warp_forward<input_t, output_t, acc_t, 2>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, key_seq_len);
break;
case 3: // 8
scaled_softmax_warp_forward<input_t, output_t, acc_t, 3>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, key_seq_len);
break;
case 4: // 16
scaled_softmax_warp_forward<input_t, output_t, acc_t, 4>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, key_seq_len);
break;
case 5: // 32
scaled_softmax_warp_forward<input_t, output_t, acc_t, 5>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, key_seq_len);
break;
case 6: // 64
scaled_softmax_warp_forward<input_t, output_t, acc_t, 6>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, key_seq_len);
break;
case 7: // 128
scaled_softmax_warp_forward<input_t, output_t, acc_t, 7>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, key_seq_len);
break;
case 8: // 256
scaled_softmax_warp_forward<input_t, output_t, acc_t, 8>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, key_seq_len);
break;
case 9: // 512
scaled_softmax_warp_forward<input_t, output_t, acc_t, 9>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, key_seq_len);
break;
case 10: // 1024
scaled_softmax_warp_forward<input_t, output_t, acc_t, 10>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, key_seq_len);
break;
case 11: // 2048
scaled_softmax_warp_forward<input_t, output_t, acc_t, 11>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, key_seq_len);
break;
case 12: // 4096
scaled_softmax_warp_forward<input_t, output_t, acc_t, 12>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, key_seq_len);
break;
default:
break;
}
}
}
template<typename input_t, typename output_t, typename acc_t>
void dispatch_scaled_masked_softmax_forward(
output_t *dst,
const input_t *src,
const uint8_t *mask,
const input_t scale,
int query_seq_len,
int key_seq_len,
int batches,
int attn_heads,
int pad_batches)
{
TORCH_INTERNAL_ASSERT(key_seq_len >= 0 && key_seq_len <= 4096 );
if (key_seq_len == 0) {
return;
} else {
int log2_elements = log2_ceil(key_seq_len);
const int next_power_of_two = 1 << log2_elements;
int batch_count = batches * attn_heads * query_seq_len;
// This value must match the WARP_SIZE constexpr value computed inside softmax_warp_forward.
int warp_size = (next_power_of_two < C10_WARP_SIZE) ? next_power_of_two : C10_WARP_SIZE;
// This value must match the WARP_BATCH constexpr value computed inside softmax_warp_forward.
int batches_per_warp = (next_power_of_two <= 128) ? 2 : 1;
// use 128 threads per block to maximimize gpu utilization
constexpr int threads_per_block = 128;
int warps_per_block = (threads_per_block / warp_size);
int batches_per_block = warps_per_block * batches_per_warp;
TORCH_INTERNAL_ASSERT(query_seq_len%batches_per_block == 0);
dim3 blocks(query_seq_len/batches_per_block, attn_heads, batches);
dim3 threads(warp_size, warps_per_block, 1);
// Launch code would be more elegant if C++ supported FOR CONSTEXPR
switch (log2_elements) {
case 0: // 1
scaled_masked_softmax_warp_forward<input_t, output_t, acc_t, 0>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, mask, scale, batch_count, key_seq_len, pad_batches);
break;
case 1: // 2
scaled_masked_softmax_warp_forward<input_t, output_t, acc_t, 1>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, mask, scale, batch_count, key_seq_len, pad_batches);
break;
case 2: // 4
scaled_masked_softmax_warp_forward<input_t, output_t, acc_t, 2>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, mask, scale, batch_count, key_seq_len, pad_batches);
break;
case 3: // 8
scaled_masked_softmax_warp_forward<input_t, output_t, acc_t, 3>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, mask, scale, batch_count, key_seq_len, pad_batches);
break;
case 4: // 16
scaled_masked_softmax_warp_forward<input_t, output_t, acc_t, 4>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, mask, scale, batch_count, key_seq_len, pad_batches);
break;
case 5: // 32
scaled_masked_softmax_warp_forward<input_t, output_t, acc_t, 5>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, mask, scale, batch_count, key_seq_len, pad_batches);
break;
case 6: // 64
scaled_masked_softmax_warp_forward<input_t, output_t, acc_t, 6>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, mask, scale, batch_count, key_seq_len, pad_batches);
break;
case 7: // 128
scaled_masked_softmax_warp_forward<input_t, output_t, acc_t, 7>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, mask, scale, batch_count, key_seq_len, pad_batches);
break;
case 8: // 256
scaled_masked_softmax_warp_forward<input_t, output_t, acc_t, 8>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, mask, scale, batch_count, key_seq_len, pad_batches);
break;
case 9: // 512
scaled_masked_softmax_warp_forward<input_t, output_t, acc_t, 9>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, mask, scale, batch_count, key_seq_len, pad_batches);
break;
case 10: // 1024
scaled_masked_softmax_warp_forward<input_t, output_t, acc_t, 10>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, mask, scale, batch_count, key_seq_len, pad_batches);
break;
case 11: // 2048
scaled_masked_softmax_warp_forward<input_t, output_t, acc_t, 11>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, mask, scale, batch_count, key_seq_len, pad_batches);
break;
case 12: // 4096
scaled_masked_softmax_warp_forward<input_t, output_t, acc_t, 12>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, mask, scale, batch_count, key_seq_len, pad_batches);
break;
default:
break;
}
}
}
template<typename input_t, typename output_t, typename acc_t>
void dispatch_scaled_masked_softmax_backward(
output_t *grad_input,
input_t *grad,
const input_t *output,
const acc_t scale,
int query_seq_len,
int key_seq_len,
int batches,
int attn_heads)
{
TORCH_INTERNAL_ASSERT( key_seq_len >= 0 && key_seq_len <= 4096 );
if (key_seq_len == 0) {
return;
} else {
int log2_elements = log2_ceil(key_seq_len);
const int next_power_of_two = 1 << log2_elements;
int batch_count = batches * attn_heads * query_seq_len;
// This value must match the WARP_SIZE constexpr value computed inside softmax_warp_backward.
int warp_size = (next_power_of_two < C10_WARP_SIZE) ? next_power_of_two : C10_WARP_SIZE;
// This value must match the WARP_BATCH constexpr value computed inside softmax_warp_backward.
int batches_per_warp = (next_power_of_two <= 128) ? 2 : 1;
// use 128 threads per block to maximimize gpu utilization
constexpr int threads_per_block = 128;
int warps_per_block = (threads_per_block / warp_size);
int batches_per_block = warps_per_block * batches_per_warp;
int blocks = batch_count/batches_per_block;
dim3 threads(warp_size, warps_per_block, 1);
// Launch code would be more elegant if C++ supported FOR CONSTEXPR
switch (log2_elements) {
case 0: // 1
scaled_masked_softmax_warp_backward<input_t, output_t, acc_t, 0>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, key_seq_len);
break;
case 1: // 2
scaled_masked_softmax_warp_backward<input_t, output_t, acc_t, 1>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, key_seq_len);
break;
case 2: // 4
scaled_masked_softmax_warp_backward<input_t, output_t, acc_t, 2>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, key_seq_len);
break;
case 3: // 8
scaled_masked_softmax_warp_backward<input_t, output_t, acc_t, 3>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, key_seq_len);
break;
case 4: // 16
scaled_masked_softmax_warp_backward<input_t, output_t, acc_t, 4>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, key_seq_len);
break;
case 5: // 32
scaled_masked_softmax_warp_backward<input_t, output_t, acc_t, 5>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, key_seq_len);
break;
case 6: // 64
scaled_masked_softmax_warp_backward<input_t, output_t, acc_t, 6>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, key_seq_len);
break;
case 7: // 128
scaled_masked_softmax_warp_backward<input_t, output_t, acc_t, 7>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, key_seq_len);
break;
case 8: // 256
scaled_masked_softmax_warp_backward<input_t, output_t, acc_t, 8>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, key_seq_len);
break;
case 9: // 512
scaled_masked_softmax_warp_backward<input_t, output_t, acc_t, 9>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, key_seq_len);
break;
case 10: // 1024
scaled_masked_softmax_warp_backward<input_t, output_t, acc_t, 10>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, key_seq_len);
break;
case 11: // 2048
scaled_masked_softmax_warp_backward<input_t, output_t, acc_t, 11>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, key_seq_len);
break;
case 12: // 4096
scaled_masked_softmax_warp_backward<input_t, output_t, acc_t, 12>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, key_seq_len);
break;
default:
break;
}
}
}
megatron/fused_kernels/scaled_masked_softmax_cuda.cu 0 → 100644
View file @ d3dd8642
/* Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved. */
#include <ATen/ATen.h>
#include <cuda.h>
#include <cuda_runtime.h>
#include <cuda_fp16.h>
#include <cuda_profiler_api.h>
#include <ATen/cuda/CUDAContext.h>
#include <torch/extension.h>
#include "scaled_masked_softmax.h"
#include "type_shim.h"
namespace multihead_attn {
namespace fused_softmax {
namespace scaled_masked_softmax {
int get_batch_per_block_cuda(int query_seq_len, int key_seq_len, int batches, int attn_heads){
return get_batch_per_block(query_seq_len, key_seq_len, batches, attn_heads);
}
torch::Tensor fwd_cuda(
torch::Tensor const& input,
torch::Tensor const& mask,
float scale_factor)
{
// input is a 4d tensor with dimensions [batches, attn_heads, seq_len, seq_len]
const int batches = input.size(0);
const int pad_batches = mask.size(0);
const int attn_heads = input.size(1);
const int query_seq_len = input.size(2);
const int key_seq_len = input.size(3);
TORCH_INTERNAL_ASSERT(key_seq_len <= 4096);
TORCH_INTERNAL_ASSERT(query_seq_len > 1);
TORCH_INTERNAL_ASSERT(pad_batches == 1 || pad_batches == batches);
TORCH_INTERNAL_ASSERT(mask.size(1) == 1);
TORCH_INTERNAL_ASSERT(mask.size(2) == query_seq_len);
TORCH_INTERNAL_ASSERT(mask.size(3) == key_seq_len);
// Output
auto act_options = input.options().requires_grad(false);
torch::Tensor softmax_results =
torch::empty({batches, attn_heads, query_seq_len, key_seq_len}, act_options);
// Softmax Intermediate Result Ptr
void* input_ptr = static_cast<void*>(input.data_ptr());
void* mask_ptr = static_cast<void*>(mask.data_ptr());
void* softmax_results_ptr = static_cast<void*>(softmax_results.data_ptr());
DISPATCH_HALF_AND_BFLOAT(
input.scalar_type(),
"dispatch_scaled_masked_softmax_forward",
dispatch_scaled_masked_softmax_forward<scalar_t, scalar_t, float>(
reinterpret_cast<scalar_t*>(softmax_results_ptr),
reinterpret_cast<const scalar_t*>(input_ptr),
reinterpret_cast<const uint8_t*>(mask_ptr),
scale_factor,
query_seq_len,
key_seq_len,
batches,
attn_heads,
pad_batches);
);
return softmax_results;
}
torch::Tensor bwd_cuda(
torch::Tensor const& output_grads_,
torch::Tensor const& softmax_results_,
float scale_factor) {
auto output_grads = output_grads_.contiguous();
auto softmax_results = softmax_results_.contiguous();
//output grads is a 4d tensor with dimensions [batches, attn_heads, seq_len, seq_len]
const int batches = output_grads.size(0);
const int attn_heads = output_grads.size(1);
const int query_seq_len = output_grads.size(2);
const int key_seq_len = output_grads.size(3);
auto act_options = output_grads.options().requires_grad(false);
torch::Tensor input_grads =
torch::empty({batches, attn_heads, query_seq_len, key_seq_len}, act_options);
void* output_grads_ptr = static_cast<void*>(output_grads.data_ptr());
void* input_grads_ptr = static_cast<void*>(input_grads.data_ptr());
//Softmax Grad
DISPATCH_HALF_AND_BFLOAT(
output_grads_.scalar_type(),
"dispatch_scaled_masked_softmax_backward",
dispatch_scaled_masked_softmax_backward<scalar_t, scalar_t, float>(
reinterpret_cast<scalar_t*>(input_grads_ptr),
reinterpret_cast<scalar_t*>(output_grads_ptr),
reinterpret_cast<scalar_t const*>(softmax_results.data_ptr()),
scale_factor,
query_seq_len,
key_seq_len,
batches,
attn_heads);
);
return input_grads;
}
}
}
}
megatron/fused_kernels/scaled_softmax.cpp 0 → 100644
View file @ d3dd8642
/* Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved. */
#include <cuda_fp16.h>
#include <torch/extension.h>
#include <vector>
namespace multihead_attn {
namespace fused_softmax {
namespace scaled_softmax {
torch::Tensor fwd_cuda(
torch::Tensor const& input,
float scale_factor);
torch::Tensor bwd_cuda(
torch::Tensor const& output_grads,
torch::Tensor const& softmax_results,
float scale_factor);
torch::Tensor fwd(
torch::Tensor const& input,
float scale_factor) {
AT_ASSERTM(input.dim() == 4, "expected 4D tensor");
AT_ASSERTM((input.scalar_type() == at::ScalarType::Half) ||
(input.scalar_type() == at::ScalarType::BFloat16),
"Only fp16 and bf16 are supported");
return fwd_cuda(input, scale_factor);
}
torch::Tensor bwd(
torch::Tensor const& output_grads,
torch::Tensor const& softmax_results,
float scale_factor) {
AT_ASSERTM(output_grads.dim() == 4, "expected 3D tensor");
AT_ASSERTM(softmax_results.dim() == 4, "expected 3D tensor");
AT_ASSERTM((output_grads.scalar_type() == at::ScalarType::Half) ||
(output_grads.scalar_type() == at::ScalarType::BFloat16),
"Only fp16 and bf16 are supported");
AT_ASSERTM((softmax_results.scalar_type() == at::ScalarType::Half) ||
(softmax_results.scalar_type() == at::ScalarType::BFloat16),
"Only fp16 and bf16 are supported");
return bwd_cuda(output_grads, softmax_results, scale_factor);
}
} // end namespace scaled_softmax
} // end namespace fused_softmax
} // end namespace multihead_attn
PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
m.def("forward",
&multihead_attn::fused_softmax::scaled_softmax::fwd,
"Self Multihead Attention scaled, softmax -- Forward.");
m.def("backward",
&multihead_attn::fused_softmax::scaled_softmax::bwd,
"Self Multihead Attention scaled, softmax -- Backward.");
}
megatron/fused_kernels/scaled_softmax_cuda.cu 0 → 100644
View file @ d3dd8642
/* Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved. */
#include <ATen/ATen.h>
#include <cuda.h>
#include <cuda_runtime.h>
#include <cuda_fp16.h>
#include <cuda_profiler_api.h>
#include <ATen/cuda/CUDAContext.h>
#include <torch/extension.h>
#include "scaled_masked_softmax.h"
#include "type_shim.h"
namespace multihead_attn {
namespace fused_softmax {
namespace scaled_softmax {
torch::Tensor fwd_cuda(
torch::Tensor const& input,
float scale_factor)
{
// input is a 4d tensor with dimensions [batches, attn_heads, seq_len, seq_len]
const int batches = input.size(0);
const int attn_heads = input.size(1);
const int query_seq_len = input.size(2);
const int key_seq_len = input.size(3);
TORCH_INTERNAL_ASSERT(key_seq_len <= 4096);
TORCH_INTERNAL_ASSERT(query_seq_len > 1);
// Output
auto act_options = input.options().requires_grad(false);
torch::Tensor softmax_results =
torch::empty({batches, attn_heads, query_seq_len, key_seq_len}, act_options);
// Softmax Intermediate Result Ptr
void* input_ptr = static_cast<void*>(input.data_ptr());
void* softmax_results_ptr = static_cast<void*>(softmax_results.data_ptr());
DISPATCH_HALF_AND_BFLOAT(
input.scalar_type(),
"dispatch_scaled_softmax_forward",
dispatch_scaled_softmax_forward<scalar_t, scalar_t, float>(
reinterpret_cast<scalar_t*>(softmax_results_ptr),
reinterpret_cast<const scalar_t*>(input_ptr),
scale_factor,
query_seq_len,
key_seq_len,
batches,
attn_heads);
);
return softmax_results;
}
torch::Tensor bwd_cuda(
torch::Tensor const& output_grads_,
torch::Tensor const& softmax_results_,
float scale_factor) {
auto output_grads = output_grads_.contiguous();
auto softmax_results = softmax_results_.contiguous();
//output grads is a 4d tensor with dimensions [batches, attn_heads, seq_len, seq_len]
const int batches = output_grads.size(0);
const int attn_heads = output_grads.size(1);
const int query_seq_len = output_grads.size(2);
const int key_seq_len = output_grads.size(3);
void* output_grads_ptr = static_cast<void*>(output_grads.data_ptr());
//Softmax Grad
DISPATCH_HALF_AND_BFLOAT(
output_grads_.scalar_type(),
"dispatch_scaled_masked_softmax_backward",
dispatch_scaled_masked_softmax_backward<scalar_t, scalar_t, float>(
reinterpret_cast<scalar_t*>(output_grads_ptr),
reinterpret_cast<scalar_t*>(output_grads_ptr),
reinterpret_cast<scalar_t const*>(softmax_results.data_ptr()),
scale_factor,
query_seq_len,
key_seq_len,
batches,
attn_heads);
);
//backward pass is completely in-place
return output_grads;
}
}
}
}
megatron/fused_kernels/scaled_upper_triang_masked_softmax.cpp 0 → 100644
View file @ d3dd8642
/* Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved. */
#include <cuda_fp16.h>
#include <torch/extension.h>
#include <vector>
namespace multihead_attn {
namespace fused_softmax {
namespace scaled_upper_triang_masked_softmax {
torch::Tensor fwd_cuda(
torch::Tensor const& input,
float scale_factor);
torch::Tensor bwd_cuda(
torch::Tensor const& output_grads,
torch::Tensor const& softmax_results,
float scale_factor);
torch::Tensor fwd(torch::Tensor const& input, float scale_factor) {
AT_ASSERTM(input.dim() == 3, "expected 3D tensor");
AT_ASSERTM((input.scalar_type() == at::ScalarType::Half) ||
(input.scalar_type() == at::ScalarType::BFloat16),
"Only fp16 and bf16 are supported");
return fwd_cuda(input, scale_factor);
}
torch::Tensor bwd(
torch::Tensor const& output_grads,
torch::Tensor const& softmax_results,
float scale_factor) {
AT_ASSERTM(output_grads.dim() == 3, "expected 3D tensor");
AT_ASSERTM(softmax_results.dim() == 3, "expected 3D tensor");
AT_ASSERTM((output_grads.scalar_type() == at::ScalarType::Half) ||
(output_grads.scalar_type() == at::ScalarType::BFloat16),
"Only fp16 and bf16 are supported");
AT_ASSERTM((softmax_results.scalar_type() == at::ScalarType::Half) ||
(softmax_results.scalar_type() == at::ScalarType::BFloat16),
"Only fp16 and bf16 are supported");
return bwd_cuda(output_grads, softmax_results, scale_factor);
}
} // end namespace scaled_upper_triang_masked_softmax
} // end namespace fused_softmax
} // end namespace multihead_attn
PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
m.def("forward",
&multihead_attn::fused_softmax::scaled_upper_triang_masked_softmax::fwd,
"Self Multihead Attention scaled, time masked softmax -- Forward.");
m.def("backward",
&multihead_attn::fused_softmax::scaled_upper_triang_masked_softmax::bwd,
"Self Multihead Attention scaled, time masked softmax -- Backward.");
}
megatron/fused_kernels/scaled_upper_triang_masked_softmax.h 0 → 100644
View file @ d3dd8642
/* Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved. */
#pragma once
#include <assert.h>
#include <cuda_fp16.h>
#include <cfloat>
#include <limits>
#include <stdint.h>
#include <c10/macros/Macros.h>
namespace {
template <typename Datatype, int ELEMENTS_PER_LDG>
__device__ __inline__ void copy_vector(Datatype *dst, const Datatype *src);
template <>
__device__ __inline__ void copy_vector<c10::BFloat16, 1>(c10::BFloat16 *dst, const c10::BFloat16 *src) { *dst = *src; }
template <>
__device__ __inline__ void copy_vector<c10::BFloat16, 4>(c10::BFloat16 *dst, const c10::BFloat16 *src) { *((float2*) dst) = *((float2*) src); }
template <>
__device__ __inline__ void copy_vector<c10::Half, 1>(c10::Half *dst, const c10::Half *src) { *dst = *src; }
template <>
__device__ __inline__ void copy_vector<c10::Half, 4>(c10::Half *dst, const c10::Half *src) { *((float2*) dst) = *((float2*) src); }
template <>
__device__ __inline__ void copy_vector<uint8_t, 1>(uint8_t *dst, const uint8_t *src) { *dst = *src; }
template <>
__device__ __inline__ void copy_vector<uint8_t, 4>(uint8_t *dst, const uint8_t *src) {*((half2*) dst) = *((half2*) src); }
template <typename Datatype, int ELEMENTS_PER_LDG>
__device__ __inline__ void copy_zero_vector(Datatype *dst);
template <>
__device__ __inline__ void copy_zero_vector<c10::BFloat16, 1>(c10::BFloat16 *dst) { *dst = 0.0; }
template <>
__device__ __inline__ void copy_zero_vector<c10::BFloat16, 4>(c10::BFloat16 *dst) { *((float2*) dst) = make_float2(0.0f, 0.0f); }
template <>
__device__ __inline__ void copy_zero_vector<c10::Half, 1>(c10::Half *dst) { *dst = 0.0; }
template <>
__device__ __inline__ void copy_zero_vector<c10::Half, 4>(c10::Half *dst) { *((float2*) dst) = make_float2(0.0f, 0.0f); }
int log2_ceil(int value) {
int log2_value = 0;
while ((1 << log2_value) < value) ++log2_value;
return log2_value;
}
template<typename T>
struct Add {
__device__ __forceinline__ T operator()(T a, T b) const {
return a + b;
}
};
template<typename T>
struct Max {
__device__ __forceinline__ T operator()(T a, T b) const {
return a < b ? b : a;
}
};
template <typename T>
__device__ __forceinline__ T WARP_SHFL_XOR_NATIVE(T value, int laneMask, int width = warpSize, unsigned int mask = 0xffffffff)
{
#if CUDA_VERSION >= 9000
return __shfl_xor_sync(mask, value, laneMask, width);
#else
return __shfl_xor(value, laneMask, width);
#endif
}
template <typename acc_t, int WARP_BATCH, int WARP_SIZE, template<typename> class ReduceOp>
__device__ __forceinline__ void warp_reduce(acc_t* sum) {
ReduceOp<acc_t> r;
#pragma unroll
for (int offset = WARP_SIZE / 2; offset > 0; offset /= 2) {
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
acc_t b = WARP_SHFL_XOR_NATIVE(sum[i], offset, WARP_SIZE);
sum[i] = r(sum[i], b);
}
}
}
/*
* Extended softmax (from native aten pytorch) with following additional features
* 1) input scaling
* 2) Implicit time (diagonal masking)
*/
template <typename input_t, typename output_t, typename acc_t, int log2_elements>
__global__ void scaled_upper_triang_masked_softmax_warp_forward(
output_t *dst,
const input_t *src,
const acc_t scale,
int micro_batch_size,
int stride,
int element_count)
{
// WARP_SIZE and WARP_BATCH must match the return values batches_per_warp and
// warp_size of method warp_softmax_forward_kernel.
constexpr int next_power_of_two = 1 << log2_elements;
constexpr int WARP_SIZE = (next_power_of_two < C10_WARP_SIZE) ? next_power_of_two : C10_WARP_SIZE;
constexpr int WARP_ITERATIONS = next_power_of_two / WARP_SIZE;
constexpr int WARP_BATCH = (next_power_of_two <= 128) ? 2 : 1;
constexpr int ELEMENTS_PER_LDG_STG = (WARP_ITERATIONS < 4) ? 1 : 4;
int first_batch = (blockDim.y * blockIdx.y + threadIdx.y) * gridDim.x * WARP_BATCH + blockIdx.x;
int local_seq = blockIdx.x + 1;
int warp_iteration_limit = (local_seq + ELEMENTS_PER_LDG_STG * WARP_SIZE - 1)/ WARP_SIZE;
// micro_batch_size might not be a multiple of WARP_BATCH. Check how
// many batches have to computed within this WARP.
int local_batches = micro_batch_size - first_batch;
if (local_batches > WARP_BATCH)
local_batches = WARP_BATCH;
// there might be multiple batches per warp. compute the index within the batch
int local_idx = threadIdx.x;
src += first_batch * stride + ELEMENTS_PER_LDG_STG * local_idx;
dst += first_batch * stride + ELEMENTS_PER_LDG_STG * local_idx;
// load data from global memory
acc_t elements[WARP_BATCH][WARP_ITERATIONS];
input_t temp_data[ELEMENTS_PER_LDG_STG];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
int batch_element_count = (i >= local_batches) ? 0 : local_seq;
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; it+=ELEMENTS_PER_LDG_STG) {
int element_index = ELEMENTS_PER_LDG_STG * local_idx + it * WARP_SIZE;
if (element_index < batch_element_count) {
copy_vector<input_t, ELEMENTS_PER_LDG_STG>(temp_data, src + i*element_count*stride + it*WARP_SIZE);
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
if ((element_index + element) < batch_element_count) {
elements[i][it+element] = (acc_t)temp_data[element] * scale;
} else {
elements[i][it + element] = -std::numeric_limits<acc_t>::infinity();
}
}
} else {
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
elements[i][it + element] = -std::numeric_limits<acc_t>::infinity();
}
}
}
}
// compute max_value
acc_t max_value[WARP_BATCH];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
max_value[i] = elements[i][0];
#pragma unroll
for (int it = 1; it < WARP_ITERATIONS; ++it) {
max_value[i] = (max_value[i] > elements[i][it]) ? max_value[i] : elements[i][it];
}
}
warp_reduce<acc_t, WARP_BATCH, WARP_SIZE, Max>(max_value);
acc_t sum[WARP_BATCH] { 0.0f };
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; ++it) {
if (it < warp_iteration_limit) {
elements[i][it] = std::exp((elements[i][it] - max_value[i]));
sum[i] += elements[i][it];
}
}
}
warp_reduce<acc_t, WARP_BATCH, WARP_SIZE, Add>(sum);
// store result
output_t out[ELEMENTS_PER_LDG_STG];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
if (i >= local_batches)
break;
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; it+=ELEMENTS_PER_LDG_STG) {
int element_index = ELEMENTS_PER_LDG_STG * local_idx + it * WARP_SIZE;
if (element_index < local_seq) {
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
if (element_index + element < local_seq) {
out[element] = elements[i][it + element] / sum[i];
} else {
out[element] = 0;
}
}
copy_vector<output_t, ELEMENTS_PER_LDG_STG>(dst + i * element_count * stride + it * WARP_SIZE, out);
} else if (element_index < element_count) {
copy_zero_vector<output_t, ELEMENTS_PER_LDG_STG>(dst + i * element_count * stride + it * WARP_SIZE);
} else {
break;
}
}
}
}
template <typename input_t, typename output_t, typename acc_t, int log2_elements>
__global__ void scaled_upper_triang_masked_softmax_warp_backward(
output_t *gradInput,
input_t *grad,
const input_t *output,
acc_t scale,
int micro_batch_size,
int stride,
int element_count)
{
// WARP_SIZE and WARP_BATCH must match the return values batches_per_warp and
// warp_size of method warp_softmax_backward_kernel.
constexpr int next_power_of_two = 1 << log2_elements;
constexpr int WARP_SIZE = (next_power_of_two < C10_WARP_SIZE) ? next_power_of_two : C10_WARP_SIZE;
constexpr int WARP_ITERATIONS = next_power_of_two / WARP_SIZE;
constexpr int WARP_BATCH = (next_power_of_two <= 128) ? 2 : 1;
constexpr int ELEMENTS_PER_LDG_STG = (WARP_ITERATIONS < 4) ? 1 : 4;
int first_batch = (blockDim.y * blockIdx.y + threadIdx.y) * gridDim.x * WARP_BATCH + blockIdx.x;
int local_seq = blockIdx.x + 1;
// micro_batch_size might not be a multiple of WARP_BATCH. Check how
// many batches have to computed within this WARP.
int local_batches = micro_batch_size - first_batch;
if (local_batches > WARP_BATCH)
local_batches = WARP_BATCH;
// there might be multiple batches per warp. compute the index within the batch
int local_idx = threadIdx.x;
// the first element to process by the current thread
int thread_offset = first_batch * stride + ELEMENTS_PER_LDG_STG * local_idx;
grad += thread_offset;
output += thread_offset;
gradInput += thread_offset;
// load data from global memory
acc_t grad_reg[WARP_BATCH][WARP_ITERATIONS] { 0.0f };
acc_t output_reg[WARP_BATCH][WARP_ITERATIONS] { 0.0f };
input_t temp_grad[ELEMENTS_PER_LDG_STG];
input_t temp_output[ELEMENTS_PER_LDG_STG];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
int batch_element_count = (i >= local_batches) ? 0 : local_seq;
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; it+=ELEMENTS_PER_LDG_STG) {
int element_index = ELEMENTS_PER_LDG_STG * local_idx + it * WARP_SIZE;
if (element_index < batch_element_count) {
copy_vector<input_t, ELEMENTS_PER_LDG_STG>(temp_grad, grad + i * element_count * stride + it * WARP_SIZE);
copy_vector<input_t, ELEMENTS_PER_LDG_STG>(temp_output, output + i * element_count * stride + it * WARP_SIZE);
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
if (element_index + element < batch_element_count) {
output_reg[i][it + element] = (acc_t)temp_output[element];
}
}
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
if (element_index + element < batch_element_count) {
grad_reg[i][it + element] = (acc_t)temp_grad[element] * output_reg[i][it + element];
}
}
}
}
}
acc_t sum[WARP_BATCH];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
sum[i] = grad_reg[i][0];
#pragma unroll
for (int it = 1; it < WARP_ITERATIONS; ++it) {
sum[i] += grad_reg[i][it];
}
}
warp_reduce<acc_t, WARP_BATCH, WARP_SIZE, Add>(sum);
// store result
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
if (i >= local_batches)
break;
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; it+=ELEMENTS_PER_LDG_STG) {
int element_index = ELEMENTS_PER_LDG_STG * local_idx + it * WARP_SIZE;
if (element_index < element_count) {
// compute gradients
output_t out[ELEMENTS_PER_LDG_STG];
#pragma unroll
for (int element = 0; element < ELEMENTS_PER_LDG_STG; ++element) {
out[element] = (output_t)(scale * (grad_reg[i][it + element] - output_reg[i][it + element] * sum[i]));
}
copy_vector<output_t, ELEMENTS_PER_LDG_STG>(gradInput + i * element_count * stride + it * WARP_SIZE, out);
}
}
}
}
} // end of anonymous namespace
template<typename input_t, typename output_t, typename acc_t>
void dispatch_scaled_upper_triang_masked_softmax_forward(
output_t *dst,
const input_t *src,
const input_t scale,
int softmax_elements,
int softmax_elements_stride,
int attn_batches)
{
TORCH_INTERNAL_ASSERT(softmax_elements >= 0 && softmax_elements <= 16384 );
if (softmax_elements == 0) {
return;
} else {
int log2_elements = log2_ceil(softmax_elements);
const int next_power_of_two = 1 << log2_elements;
int seq_len = softmax_elements;
int batch_count = attn_batches * seq_len;
// This value must match the WARP_SIZE constexpr value computed inside softmax_warp_forward.
int warp_size = (next_power_of_two < C10_WARP_SIZE) ? next_power_of_two : C10_WARP_SIZE;
// This value must match the WARP_BATCH constexpr value computed inside softmax_warp_forward.
int batches_per_warp = (next_power_of_two <= 128) ? 2 : 1;
// use 128 threads per block to maximimize gpu utilization
constexpr int threads_per_block = 128;
int warps_per_block = (threads_per_block / warp_size);
int batches_per_block = warps_per_block * batches_per_warp;
TORCH_INTERNAL_ASSERT(attn_batches % batches_per_block == 0);
int blocks_per_seq = attn_batches / batches_per_block;
dim3 blocks(seq_len, blocks_per_seq, 1);
dim3 threads(warp_size, warps_per_block, 1);
// Launch code would be more elegant if C++ supported FOR CONSTEXPR
switch (log2_elements) {
case 0: // 1
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 0>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 1: // 2
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 1>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 2: // 4
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 2>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 3: // 8
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 3>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 4: // 16
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 4>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 5: // 32
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 5>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 6: // 64
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 6>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 7: // 128
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 7>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 8: // 256
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 8>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 9: // 512
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 9>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 10: // 1024
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 10>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 11: // 2048
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 11>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 12: // 4096
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 12>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 13: // 8192
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 13>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 14: // 16384
scaled_upper_triang_masked_softmax_warp_forward<input_t, output_t, acc_t, 14>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(dst, src, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
default:
break;
}
}
}
template<typename input_t, typename output_t, typename acc_t>
void dispatch_scaled_upper_triang_masked_softmax_backward(
output_t *grad_input,
input_t *grad,
const input_t *output,
const acc_t scale,
int softmax_elements,
int softmax_elements_stride,
int attn_batches)
{
TORCH_INTERNAL_ASSERT( softmax_elements >= 0 && softmax_elements <= 16384 );
if (softmax_elements == 0) {
return;
} else {
int log2_elements = log2_ceil(softmax_elements);
const int next_power_of_two = 1 << log2_elements;
int seq_len = softmax_elements;
int batch_count = attn_batches * seq_len;
// This value must match the WARP_SIZE constexpr value computed inside softmax_warp_backward.
int warp_size = (next_power_of_two < C10_WARP_SIZE) ? next_power_of_two : C10_WARP_SIZE;
// This value must match the WARP_BATCH constexpr value computed inside softmax_warp_backward.
int batches_per_warp = (next_power_of_two <= 128) ? 2 : 1;
// use 128 threads per block to maximimize gpu utilization
constexpr int threads_per_block = 128;
int warps_per_block = (threads_per_block / warp_size);
int batches_per_block = warps_per_block * batches_per_warp;
TORCH_INTERNAL_ASSERT(attn_batches % batches_per_block == 0);
int blocks_per_seq = attn_batches / batches_per_block;
dim3 blocks(seq_len, blocks_per_seq, 1);
dim3 threads(warp_size, warps_per_block, 1);
// Launch code would be more elegant if C++ supported FOR CONSTEXPR
switch (log2_elements) {
case 0: // 1
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 0>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 1: // 2
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 1>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 2: // 4
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 2>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 3: // 8
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 3>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 4: // 16
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 4>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 5: // 32
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 5>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 6: // 64
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 6>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 7: // 128
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 7>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 8: // 256
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 8>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 9: // 512
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 9>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 10: // 1024
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 10>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 11: // 2048
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 11>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 12: // 4096
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 12>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 13: // 8192
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 13>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
case 14: // 16384
scaled_upper_triang_masked_softmax_warp_backward<input_t, output_t, acc_t, 14>
<<<blocks, threads, 0, at::cuda::getCurrentCUDAStream()>>>(grad_input, grad, output, scale, batch_count, softmax_elements_stride, softmax_elements);
break;
default:
break;
}
}
}
megatron/fused_kernels/scaled_upper_triang_masked_softmax_cuda.cu 0 → 100644
View file @ d3dd8642
/* Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved. */
#include <ATen/ATen.h>
#include <cuda.h>
#include <cuda_runtime.h>
#include <cuda_fp16.h>
#include <cuda_profiler_api.h>
#include <ATen/cuda/CUDAContext.h>
#include <torch/extension.h>
#include "scaled_upper_triang_masked_softmax.h"
#include "type_shim.h"
namespace multihead_attn {
namespace fused_softmax {
namespace scaled_upper_triang_masked_softmax {
torch::Tensor fwd_cuda(
torch::Tensor const& input,
float scale_factor)
{
// input is a 3d tensor with dimensions [attn_batches, seq_len, seq_len]
const int attn_batches = input.size(0);
const int seq_len = input.size(1);
TORCH_INTERNAL_ASSERT(seq_len <= 16384);
// Output
auto act_options = input.options().requires_grad(false);
torch::Tensor softmax_results =
torch::empty({attn_batches, seq_len, seq_len}, act_options);
// Softmax Intermediate Result Ptr
void* input_ptr = static_cast<void*>(input.data_ptr());
void* softmax_results_ptr = static_cast<void*>(softmax_results.data_ptr());
DISPATCH_HALF_AND_BFLOAT(
input.scalar_type(),
"dispatch_scaled_upper_triang_masked_softmax_forward",
dispatch_scaled_upper_triang_masked_softmax_forward<scalar_t, scalar_t, float>(
reinterpret_cast<scalar_t*>(softmax_results_ptr),
reinterpret_cast<const scalar_t*>(input_ptr),
scale_factor,
seq_len,
seq_len,
attn_batches);
);
return softmax_results;
}
torch::Tensor bwd_cuda(
torch::Tensor const& output_grads_,
torch::Tensor const& softmax_results_,
float scale_factor) {
auto output_grads = output_grads_.contiguous();
auto softmax_results = softmax_results_.contiguous();
//output grads is a 3d tensor with dimensions [attn_batches, seq_len, seq_len]
const int attn_batches = output_grads.size(0);
const int seq_len = output_grads.size(1);
TORCH_INTERNAL_ASSERT(output_grads.size(1) == output_grads.size(2));
void* output_grads_ptr = static_cast<void*>(output_grads.data_ptr());
//Softmax Grad
DISPATCH_HALF_AND_BFLOAT(
output_grads_.scalar_type(),
"dispatch_scaled_upper_triang_masked_softmax_backward",
dispatch_scaled_upper_triang_masked_softmax_backward<scalar_t, scalar_t, float>(
reinterpret_cast<scalar_t*>(output_grads_ptr),
reinterpret_cast<scalar_t*>(output_grads_ptr),
reinterpret_cast<scalar_t const*>(softmax_results.data_ptr()),
scale_factor,
seq_len,
seq_len,
attn_batches);
);
//backward pass is completely in-place
return output_grads;
}
}
}
}
megatron/fused_kernels/tests/test_fused_kernels.py 0 → 100644
View file @ d3dd8642
import math
import torch
from torch.nn import LayerNorm
from megatron.model.enums import AttnMaskType
from megatron.model.fused_layer_norm import MixedFusedLayerNorm
from megatron.model.fused_softmax import FusedScaleMaskSoftmax
from megatron.model.utils import attention_mask_func
from megatron.fused_kernels import load
def test_load_fused_kernels():
try:
import fused_layer_norm_cuda
import scaled_masked_softmax_cuda
import scaled_upper_triang_masked_softmax_cuda
import torch
print("[Success] load_fused_kernels")
except ImportError as e:
print("[Fail] load_fused_kernels")
raise e
def test_fused_softmax():
bert = BertModel.from_pretrained("bert-base-cased").cuda().half()
tokenizer = BertTokenizer.from_pretrained("bert-base-cased")
test_text = (
"Hello. How are you? I am fine thank you and you? yes Good. "
"hi hi hi hi hi hi hi hi hi hi hi hi hi" # 32
)
tokens = tokenizer(
[test_text] * 4,
return_tensors="pt",
)
embedding_output = bert.embeddings(
input_ids=tokens["input_ids"].cuda(),
position_ids=None,
token_type_ids=tokens["token_type_ids"].cuda(),
inputs_embeds=None,
past_key_values_length=0,
)
# (bsz, 1, 1, seq_len)
mask = bert.get_extended_attention_mask(
attention_mask=tokens["attention_mask"].cuda(),
input_shape=tokens["input_ids"].shape,
device=bert.device,
)
# (bsz, 1, seq_len, seq_len)
mask = mask.repeat(1, 1, mask.size()[-1], 1)
attention = bert.encoder.layer[0].attention.self
key_layer = attention.transpose_for_scores(attention.key(embedding_output))
query_layer = attention.transpose_for_scores(attention.query(embedding_output))
attention_scores = torch.matmul(query_layer, key_layer.transpose(-1, -2))
attention_scores /= math.sqrt(key_layer.size()[-1])
fused_softmax = (
FusedScaleMaskSoftmax(
input_in_fp16=True,
input_in_bf16=False,
mask_func=attention_mask_func,
scale=None,
softmax_in_fp32=False,
attn_mask_type=AttnMaskType.padding,
scaled_masked_softmax_fusion=True,
)
.cuda()
.half()
)
fused_softmax_output = fused_softmax(
attention_scores,
(mask != 0),
)
torch_softmax = (
FusedScaleMaskSoftmax(
input_in_fp16=True,
input_in_bf16=False,
mask_func=attention_mask_func,
scale=None,
softmax_in_fp32=False,
attn_mask_type=AttnMaskType.padding,
scaled_masked_softmax_fusion=False,
)
.cuda()
.half()
)
torch_softmax_output = torch_softmax(
attention_scores,
(mask != 0),
)
test_result = (fused_softmax_output - torch_softmax_output).abs()
while test_result.dim() != 1:
test_result = test_result.mean(dim=-1)
diff = test_result.mean(dim=-1)
if diff <= 1e-3:
print(
f"\n[Success] test_fused_softmax"
f"\n > mean_difference={diff}"
f"\n > fused_values={fused_softmax_output[-1][-1][-1][:5].tolist()}"
f"\n > torch_values={torch_softmax_output[-1][-1][-1][:5].tolist()}"
)
else:
print(
f"\n[Fail] test_fused_softmax"
f"\n > mean_difference={diff}, "
f"\n > fused_values={fused_softmax_output[-1][-1][-1][:5].tolist()}, "
f"\n > torch_values={torch_softmax_output[-1][-1][-1][:5].tolist()}"
)
def test_fused_upper_triangle_mask_softmax():
gpt = GPT2Model.from_pretrained("gpt2").cuda().half()
tokenizer = GPT2Tokenizer.from_pretrained("gpt2")
test_text = (
"Hello. How are you? I am fine thank you and you? yes Good. "
"hi hi hi hi hi hi hi" # 24
)
tokens = tokenizer(
[test_text] * 4,
return_tensors="pt",
)
attention_mask = tokens["attention_mask"].cuda()
attention_mask = attention_mask.view(attention_mask.size(0), -1)
attention_mask = attention_mask[:, None, None, :]
attention_mask = (1.0 - attention_mask) * -10000.0
attention_mask = attention_mask.repeat(1, 1, attention_mask.size()[-1], 1)
attn = gpt.h[0]
hidden_states = gpt.wte(tokens["input_ids"].cuda())
q, k, v = attn.attn.c_attn(hidden_states).split(768, dim=-1)
q = attn.attn._split_heads(q, attn.attn.num_heads, attn.attn.head_dim)
k = attn.attn._split_heads(k, attn.attn.num_heads, attn.attn.head_dim)
attn_weights = torch.matmul(q, k.transpose(-1, -2))
sq, sk = q.size(-2), k.size(-2)
causal_mask = attn.attn.bias[:, :, sk - sq : sk, :sk].bool()
total_mask = ~(causal_mask & (attention_mask == 0))
"""
tensor([[[[False, True, True, ..., True, True, True],
[False, False, True, ..., True, True, True],
[False, False, False, ..., True, True, True],
...,
[False, False, False, ..., False, True, True],
[False, False, False, ..., False, False, True],
[False, False, False, ..., False, False, False]]]
"""
fused_softmax = (
FusedScaleMaskSoftmax(
input_in_fp16=True,
input_in_bf16=False,
mask_func=attention_mask_func,
scale=None,
softmax_in_fp32=False,
attn_mask_type=AttnMaskType.causal,
scaled_masked_softmax_fusion=True,
)
.cuda()
.half()
)
fused_softmax_output = fused_softmax(
attn_weights,
total_mask,
)
torch_softmax = (
FusedScaleMaskSoftmax(
input_in_fp16=True,
input_in_bf16=False,
mask_func=attention_mask_func,
scale=None,
softmax_in_fp32=False,
attn_mask_type=AttnMaskType.causal,
scaled_masked_softmax_fusion=False,
)
.cuda()
.half()
)
torch_softmax_output = torch_softmax(
attn_weights,
total_mask,
)
test_result = (fused_softmax_output - torch_softmax_output).abs()
while test_result.dim() != 1:
test_result = test_result.mean(dim=-1)
diff = test_result.mean(dim=-1)
if diff <= 1e-3:
print(
f"\n[Success] test_fused_upper_triangle_mask_softmax"
f"\n > mean_difference={diff}"
f"\n > fused_values={fused_softmax_output[-1][-1][-1][:5].tolist()}"
f"\n > torch_values={torch_softmax_output[-1][-1][-1][:5].tolist()}"
)
else:
print(
f"\n[Fail] test_fused_upper_triangle_mask_softmax"
f"\n > mean_difference={diff}, "
f"\n > fused_values={fused_softmax_output[-1][-1][-1][:5].tolist()}, "
f"\n > torch_values={torch_softmax_output[-1][-1][-1][:5].tolist()}"
)
def test_layer_norm():
bert = BertModel.from_pretrained("bert-base-cased").cuda().half()
tokenizer = BertTokenizer.from_pretrained("bert-base-cased")
test_text = (
"Hello. How are you? I am fine thank you and you? yes Good. "
"hi hi hi hi hi hi hi hi hi hi hi hi hi" # 32
)
tokens = tokenizer(
[test_text] * 4,
return_tensors="pt",
)
# [bsz, seq_len, d_model]
embedding_output = (
bert.embeddings(
input_ids=tokens["input_ids"].cuda(),
position_ids=None,
token_type_ids=tokens["token_type_ids"].cuda(),
inputs_embeds=None,
past_key_values_length=0,
)
.cuda()
.half()
)
fused_layernorm_layer = (
MixedFusedLayerNorm(normalized_shape=embedding_output.size(-1)).cuda().half()
)
torch_layernorm_layer = (
LayerNorm(normalized_shape=embedding_output.size(-1)).cuda().half()
)
fused_output = fused_layernorm_layer(embedding_output)
torch_output = torch_layernorm_layer(embedding_output)
test_result = (fused_output - torch_output).abs()
while test_result.dim() != 1:
test_result = test_result.mean(dim=-1)
diff = test_result.mean(dim=-1)
if diff <= 1e-3:
print(
f"\n[Success] test_layer_norm"
f"\n > mean_difference={diff}"
f"\n > fused_values={fused_output[-1][-1][:5].tolist()}"
f"\n > torch_values={torch_output[-1][-1][:5].tolist()}"
)
else:
print(
f"\n[Fail] test_layer_norm"
f"\n > mean_difference={diff}, "
f"\n > fused_values={fused_output[-1][-1][:5].tolist()}, "
f"\n > torch_values={torch_output[-1][-1][:5].tolist()}"
)
def attention_mask_func(attention_scores, attention_mask):
attention_scores.masked_fill_(attention_mask, -10000.0)
return attention_scores
def forward_torch_softmax(input, mask, scale):
input = input * scale
mask_output = attention_mask_func(input, mask) if mask is not None else input
probs = torch.nn.Softmax(dim=-1)(mask_output)
return probs
def test_masked_softmax_forward():
import scaled_masked_softmax_cuda
batch = 2
attn = 16
scale_t = torch.tensor([1.0])
for qlen in [128, 256, 1024, 2048, 4096]:
for klen in [128, 256, 1024, 2048]:
inputs = torch.normal(0, 2, (batch, attn, qlen, klen), dtype=torch.float16, device='cuda:0')
masks = torch.randint(0, 2, (batch, 1, qlen, klen), dtype=torch.bool, device='cuda:0')
softmax_results = scaled_masked_softmax_cuda.forward(inputs, masks, scale_t[0].item())
softmax_results_torch = forward_torch_softmax(inputs, masks, scale_t[0].item())
error = (softmax_results_torch - softmax_results).abs().max()
assert error < 1e-3
def test_masked_softmax_backward():
import scaled_masked_softmax_cuda
batch = 2
attn = 16
scale_t = torch.tensor([1.0])
for qlen in [128, 256, 1024, 2048, 4096]:
for klen in [128, 256, 1024, 2048]:
inputs = torch.normal(0, 2, (batch, attn, qlen, klen), dtype=torch.float16, device='cuda:0')
backward = torch.rand_like(inputs, dtype=torch.float16, device='cuda:0')
masks = torch.randint(0, 2, (batch, 1, qlen, klen), dtype=torch.bool, device='cuda:0')
softmax_results = scaled_masked_softmax_cuda.forward(inputs, masks, scale_t[0].item())
back_grad = scaled_masked_softmax_cuda.backward(backward, softmax_results, scale_t[0].item())
inputs.requires_grad = True
softmax_results_torch = forward_torch_softmax(inputs, masks, scale_t[0].item())
softmax_results_torch.backward(backward)
error = (back_grad - inputs.grad).abs().max()
assert error < 1e-3
def test_allmasked_softmax_forward():
import scaled_masked_softmax_cuda
batch = 2
attn = 16
scale_t = torch.tensor([1.0])
for qlen in [128, 256, 1024, 2048, 4096]:
for klen in [128, 256, 1024, 2048]:
inputs = torch.normal(0, 2, (batch, attn, qlen, klen), dtype=torch.float16, device='cuda:0')
masks = torch.ones((batch, 1, qlen, klen), dtype=torch.bool, device='cuda:0')
softmax_results = scaled_masked_softmax_cuda.forward(inputs, masks, scale_t[0].item())
softmax_results_torch = torch.zeros_like(inputs)
error = (softmax_results_torch - softmax_results).abs().max()
assert error == 0.0
def test_allmasked_softmax_backward():
import scaled_masked_softmax_cuda
batch = 2
attn = 16
scale_t = torch.tensor([1.0])
for qlen in [128, 256, 1024, 2048, 4096]:
for klen in [128, 256, 1024, 2048]:
inputs = torch.normal(0, 2, (batch, attn, qlen, klen), dtype=torch.float16, device='cuda:0')
backward = torch.rand_like(inputs, dtype=torch.float16, device='cuda:0')
masks = torch.ones((batch, 1, qlen, klen), dtype=torch.bool, device='cuda:0')
softmax_results = scaled_masked_softmax_cuda.forward(inputs, masks, scale_t[0].item())
back_grad = scaled_masked_softmax_cuda.backward(backward, softmax_results, scale_t[0].item())
inputs.requires_grad = True
softmax_results_torch = forward_torch_softmax(inputs, masks, scale_t[0].item())
softmax_results_torch.backward(backward)
error = (back_grad - inputs.grad).abs().max()
assert error < 1e-3
if __name__ == "__main__":
try:
from transformers import BertTokenizer, GPT2Tokenizer
from transformers.models.bert.modeling_bert import BertModel
from transformers.models.gpt2.modeling_gpt2 import GPT2Model
import transformers
transformers.logging.set_verbosity(
transformers.logging.FATAL,
)
except:
print("\n[Fail] Please install `transformers` package to test fused kernels\n")
exit(-1)
load()
test_masked_softmax_forward()
test_masked_softmax_backward()
test_allmasked_softmax_forward()
test_allmasked_softmax_backward()
test_load_fused_kernels()
test_fused_softmax()
test_fused_upper_triangle_mask_softmax()
test_layer_norm()
megatron/fused_kernels/type_shim.h 0 → 100644
View file @ d3dd8642
/* Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved. */
#include <ATen/ATen.h>
#include "compat.h"
#define DISPATCH_HALF_AND_BFLOAT(TYPE, NAME, ...) \
switch(TYPE) \
{ \
case at::ScalarType::Half: \
{ \
using scalar_t = at::Half; \
__VA_ARGS__; \
break; \
} \
case at::ScalarType::BFloat16: \
{ \
using scalar_t = at::BFloat16; \
__VA_ARGS__; \
break; \
} \
default: \
AT_ERROR(#NAME, " not implemented for '", toString(TYPE), "'"); \
}
#define DISPATCH_HALF_BFLOAT_AND_FLOAT(TYPE, NAME, ...) \
switch(TYPE) \
{ \
case at::ScalarType::Half: \
{ \
using scalar_t = at::Half; \
__VA_ARGS__; \
break; \
} \
case at::ScalarType::BFloat16: \
{ \
using scalar_t = at::BFloat16; \
__VA_ARGS__; \
break; \
} \
case at::ScalarType::Float: \
{ \
using scalar_t = float; \
__VA_ARGS__; \
break; \
} \
default: \
AT_ERROR(#NAME, " not implemented for '", toString(TYPE), "'"); \
}
#define DISPATCH_FLOAT_HALF_AND_BFLOAT_INOUT_TYPES(TYPEIN, TYPEOUT, NAME, ...) \
switch(TYPEIN) \
{ \
case at::ScalarType::Float: \
{ \
using scalar_t_in = float; \
switch(TYPEOUT) \
{ \
case at::ScalarType::Float: \
{ \
using scalar_t_out = float; \
__VA_ARGS__; \
break; \
} \
case at::ScalarType::Half: \
{ \
using scalar_t_out = at::Half; \
__VA_ARGS__; \
break; \
} \
case at::ScalarType::BFloat16: \
{ \
using scalar_t_out = at::BFloat16; \
__VA_ARGS__; \
break; \
} \
default: \
AT_ERROR(#NAME, " not implemented for '", toString(TYPEOUT), "'"); \
} \
break; \
} \
case at::ScalarType::Half: \
{ \
using scalar_t_in = at::Half; \
using scalar_t_out = at::Half; \
__VA_ARGS__; \
break; \
} \
case at::ScalarType::BFloat16: \
{ \
using scalar_t_in = at::BFloat16; \
using scalar_t_out = at::BFloat16; \
__VA_ARGS__; \
break; \
} \
default: \
AT_ERROR(#NAME, " not implemented for '", toString(TYPEIN), "'"); \
}
megatron/global_vars.py 0 → 100644
View file @ d3dd8642
# Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
"""Megatron global variables."""
import os
import sys
import torch
from megatron import dist_signal_handler
from megatron.tokenizer import build_tokenizer
from .microbatches import build_num_microbatches_calculator
from .timers import Timers
_GLOBAL_ARGS = None
_GLOBAL_RETRO_ARGS = None
_GLOBAL_NUM_MICROBATCHES_CALCULATOR = None
_GLOBAL_TOKENIZER = None
_GLOBAL_TENSORBOARD_WRITER = None
_GLOBAL_ADLR_AUTORESUME = None
_GLOBAL_TIMERS = None
_GLOBAL_SIGNAL_HANDLER = None
def get_args():
"""Return arguments."""
_ensure_var_is_initialized(_GLOBAL_ARGS, 'args')
return _GLOBAL_ARGS
def get_retro_args():
"""Return retro arguments."""
return _GLOBAL_RETRO_ARGS
def get_num_microbatches():
return _GLOBAL_NUM_MICROBATCHES_CALCULATOR.get()
def get_current_global_batch_size():
return _GLOBAL_NUM_MICROBATCHES_CALCULATOR.get_current_global_batch_size()
def update_num_microbatches(consumed_samples, consistency_check=True):
_GLOBAL_NUM_MICROBATCHES_CALCULATOR.update(consumed_samples,
consistency_check)
def get_tokenizer():
"""Return tokenizer."""
_ensure_var_is_initialized(_GLOBAL_TOKENIZER, 'tokenizer')
return _GLOBAL_TOKENIZER
def get_tensorboard_writer():
"""Return tensorboard writer. It can be None so no need
to check if it is initialized."""
return _GLOBAL_TENSORBOARD_WRITER
def get_adlr_autoresume():
"""ADLR autoresume object. It can be None so no need
to check if it is initialized."""
return _GLOBAL_ADLR_AUTORESUME
def get_timers():
"""Return timers."""
_ensure_var_is_initialized(_GLOBAL_TIMERS, 'timers')
return _GLOBAL_TIMERS
def get_signal_handler():
_ensure_var_is_initialized(_GLOBAL_SIGNAL_HANDLER, 'signal handler')
return _GLOBAL_SIGNAL_HANDLER
def _set_signal_handler():
global _GLOBAL_SIGNAL_HANDLER
_ensure_var_is_not_initialized(_GLOBAL_SIGNAL_HANDLER, 'signal handler')
_GLOBAL_SIGNAL_HANDLER = dist_signal_handler.DistributedSignalHandler().__enter__()
def set_global_variables(args, build_tokenizer=True):
"""Set args, tokenizer, tensorboard-writer, adlr-autoresume, and timers."""
assert args is not None
_ensure_var_is_not_initialized(_GLOBAL_ARGS, 'args')
set_args(args)
_build_num_microbatches_calculator(args)
if build_tokenizer:
_ = _build_tokenizer(args)
_set_tensorboard_writer(args)
_set_adlr_autoresume(args)
_set_timers(args)
if args.exit_signal_handler:
_set_signal_handler()
def set_args(args):
global _GLOBAL_ARGS
_GLOBAL_ARGS = args
def set_retro_args(retro_args):
global _GLOBAL_RETRO_ARGS
_GLOBAL_RETRO_ARGS = retro_args
def _build_num_microbatches_calculator(args):
global _GLOBAL_NUM_MICROBATCHES_CALCULATOR
_ensure_var_is_not_initialized(_GLOBAL_NUM_MICROBATCHES_CALCULATOR,
'num microbatches calculator')
_GLOBAL_NUM_MICROBATCHES_CALCULATOR = build_num_microbatches_calculator(
args)
def _build_tokenizer(args):
"""Initialize tokenizer."""
global _GLOBAL_TOKENIZER
_ensure_var_is_not_initialized(_GLOBAL_TOKENIZER, 'tokenizer')
_GLOBAL_TOKENIZER = build_tokenizer(args)
return _GLOBAL_TOKENIZER
def rebuild_tokenizer(args):
global _GLOBAL_TOKENIZER
_GLOBAL_TOKENIZER = None
return _build_tokenizer(args)
def _set_tensorboard_writer(args):
"""Set tensorboard writer."""
global _GLOBAL_TENSORBOARD_WRITER
_ensure_var_is_not_initialized(_GLOBAL_TENSORBOARD_WRITER,
'tensorboard writer')
if hasattr(args, 'tensorboard_dir') and \
args.tensorboard_dir and args.rank == (args.world_size - 1):
try:
from torch.utils.tensorboard import SummaryWriter
print('> setting tensorboard ...')
_GLOBAL_TENSORBOARD_WRITER = SummaryWriter(
log_dir=args.tensorboard_dir,
max_queue=args.tensorboard_queue_size)
except ModuleNotFoundError:
print('WARNING: TensorBoard writing requested but is not '
'available (are you using PyTorch 1.1.0 or later?), '
'no TensorBoard logs will be written.', flush=True)
def _set_adlr_autoresume(args):
"""Initialize ADLR autoresume."""
global _GLOBAL_ADLR_AUTORESUME
_ensure_var_is_not_initialized(_GLOBAL_ADLR_AUTORESUME, 'adlr autoresume')
if args.adlr_autoresume:
if args.rank == 0:
print('enabling autoresume ...', flush=True)
sys.path.append(os.environ.get('SUBMIT_SCRIPTS', '.'))
try:
from userlib.auto_resume import AutoResume
except BaseException:
print('ADLR autoresume is not available, exiting ...')
sys.exit()
_GLOBAL_ADLR_AUTORESUME = AutoResume
def _set_timers(args):
"""Initialize timers."""
global _GLOBAL_TIMERS
_ensure_var_is_not_initialized(_GLOBAL_TIMERS, 'timers')
_GLOBAL_TIMERS = Timers(args.timing_log_level, args.timing_log_option)
def _ensure_var_is_initialized(var, name):
"""Make sure the input variable is not None."""
assert var is not None, '{} is not initialized.'.format(name)
def _ensure_var_is_not_initialized(var, name):
"""Make sure the input variable is not None."""
assert var is None, '{} is already initialized.'.format(name)
megatron/indexer.py 0 → 100644
View file @ d3dd8642
import sys
import time
import torch
import torch.distributed as dist
from megatron import get_args, print_rank_0
from megatron.core import mpu
from megatron.checkpointing import load_biencoder_checkpoint
from megatron.data.orqa_wiki_dataset import get_open_retrieval_wiki_dataset
from megatron.data.orqa_wiki_dataset import get_open_retrieval_batch
from megatron.data.biencoder_dataset_utils import get_one_epoch_dataloader
from megatron.data.realm_index import detach, OpenRetreivalDataStore
from megatron.model.biencoder_model import get_model_provider
from megatron.training import get_model
class IndexBuilder(object):
"""
Object for taking one pass over a dataset and creating a BlockData of its
embeddings
"""
def __init__(self):
args = get_args()
self.model = None
self.dataloader = None
self.evidence_embedder_obj = None
self.biencoder_shared_query_context_model = \
args.biencoder_shared_query_context_model
# need to know whether we're using a REALM checkpoint (args.load)
# or ICT checkpoint
assert not (args.load and args.ict_load)
self.log_interval = args.indexer_log_interval
self.batch_size = args.indexer_batch_size
self.load_attributes()
self.is_main_builder = mpu.get_data_parallel_rank() == 0
self.num_total_builders = mpu.get_data_parallel_world_size()
self.iteration = self.total_processed = 0
def load_attributes(self):
"""
Load the necessary attributes: model, dataloader and empty BlockData
"""
only_context_model = True
if self.biencoder_shared_query_context_model:
only_context_model = False
model = get_model(get_model_provider(only_context_model=\
only_context_model, biencoder_shared_query_context_model=\
self.biencoder_shared_query_context_model))
self.model = load_biencoder_checkpoint(model,
only_context_model=only_context_model)
assert len(self.model) == 1
self.model[0].eval()
self.dataset = get_open_retrieval_wiki_dataset()
self.dataloader = iter(get_one_epoch_dataloader(self.dataset, \
self.batch_size))
self.evidence_embedder_obj = OpenRetreivalDataStore( \
load_from_path=False)
def track_and_report_progress(self, batch_size):
"""
Utility function for tracking progress
"""
self.iteration += 1
self.total_processed += batch_size * self.num_total_builders
if self.is_main_builder and self.iteration % self.log_interval == 0:
print('Batch {:10d} | Total {:10d}'.format(self.iteration,
self.total_processed), flush=True)
def build_and_save_index(self):
"""
Goes through one epoch of the dataloader and adds all data to this
instance's BlockData.
The copy of BlockData is saved as a shard, which when run in a
distributed setting will be consolidated by the rank 0 process
and saved as a final pickled BlockData.
"""
assert len(self.model) == 1
unwrapped_model = self.model[0]
while not hasattr(unwrapped_model, 'embed_text'):
unwrapped_model = unwrapped_model.module
while True:
try:
# batch also has query_tokens and query_pad_data
row_id, context_tokens, context_mask, context_types, \
context_pad_mask = get_open_retrieval_batch( \
self.dataloader)
except (StopIteration, IndexError):
break
# TODO: can we add with torch.no_grad() to reduce memory usage
# detach, separate fields and add to BlockData
assert context_mask.dtype == torch.bool
context_logits = unwrapped_model.embed_text(
unwrapped_model.context_model, context_tokens, context_mask,
context_types)
context_logits = detach(context_logits)
row_id = detach(row_id)
self.evidence_embedder_obj.add_block_data(row_id, context_logits)
self.track_and_report_progress(batch_size=len(row_id))
# This process signals to finalize its shard and then synchronize with
# the other processes
self.evidence_embedder_obj.save_shard()
torch.distributed.barrier()
del self.model
# rank 0 process builds the final copy
if self.is_main_builder:
self.evidence_embedder_obj.merge_shards_and_save()
# make sure that every single piece of data was embedded
assert len(self.evidence_embedder_obj.embed_data) == \
len(self.dataset)
self.evidence_embedder_obj.clear()
# complete building the final copy
torch.distributed.barrier()
megatron/initialize.py 0 → 100644
View file @ d3dd8642
# Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
"""Megatron initialization."""
import random
import os
import time
import numpy as np
import torch
from datetime import timedelta
from megatron import fused_kernels
from megatron import get_adlr_autoresume
from megatron import get_args
from megatron import get_tensorboard_writer
from megatron.core import mpu, tensor_parallel
from megatron.arguments import (parse_args, validate_args)
from megatron.checkpointing import load_args_from_checkpoint
from megatron.global_vars import set_global_variables
from megatron.model.transformer import bias_dropout_add_fused_train
from megatron.model.fused_bias_gelu import bias_gelu
def initialize_megatron(extra_args_provider=None, args_defaults={},
ignore_unknown_args=False, allow_no_cuda=False):
"""Set global variables, initialize distributed, and
set autoresume and random seeds.
`allow_no_cuda` should not be set unless using megatron for cpu only
data processing. In general this arg should not be set unless you know
what you are doing.
Returns a function to finalize distributed env initialization
(optionally, only when args.lazy_mpu_init == True)
"""
if not allow_no_cuda:
# Make sure cuda is available.
assert torch.cuda.is_available(), 'Megatron requires CUDA.'
# Parse arguments
args = parse_args(extra_args_provider, ignore_unknown_args)
if args.use_checkpoint_args or args_defaults.get('use_checkpoint_args', False):
assert args.load is not None, '--use-checkpoints-args requires --load argument'
load_args_from_checkpoint(args)
validate_args(args, args_defaults)
# set global args, build tokenizer, and set adlr-autoresume,
# tensorboard-writer, and timers.
set_global_variables(args)
# torch.distributed initialization
def finish_mpu_init():
args = get_args()
# Pytorch distributed.
_initialize_distributed()
# Random seeds for reproducibility.
if args.rank == 0:
print('> setting random seeds to {} ...'.format(args.seed))
_set_random_seed(args.seed, args.data_parallel_random_init)
args = get_args()
if args.lazy_mpu_init:
# TODO is this still a necessary option?
args.use_cpu_initialization=True
# delayed initialization of DDP-related stuff
# We only set basic DDP globals
mpu.set_tensor_model_parallel_world_size(args.tensor_model_parallel_size)
# and return function for external DDP manager
# to call when it has DDP initialized
mpu.set_tensor_model_parallel_rank(args.rank)
return finish_mpu_init
else:
# Megatron's MPU is the master. Complete initialization right away.
finish_mpu_init()
# Autoresume.
_init_autoresume()
# Compile dependencies.
_compile_dependencies()
# No continuation function
return None
def _compile_dependencies():
args = get_args()
# =========================
# Compile dataset C++ code.
# =========================
# TODO: move this to ninja
if torch.distributed.get_rank() == 0:
start_time = time.time()
print('> compiling dataset index builder ...')
from megatron.data.dataset_utils import compile_helper
compile_helper()
print('>>> done with dataset index builder. Compilation time: {:.3f} '
'seconds'.format(time.time() - start_time), flush=True)
# ==================
# Load fused kernels
# ==================
# Custom kernel constraints check.
seq_len = args.seq_length
attn_batch_size = \
(args.num_attention_heads / args.tensor_model_parallel_size) * \
args.micro_batch_size
# Constraints on sequence length and attn_batch_size to enable warp based
# optimization and upper triangular optimization (for causal mask)
custom_kernel_constraint = seq_len > 16 and seq_len <=4096 and \
seq_len % 4 == 0 and attn_batch_size % 4 == 0
# Print a warning.
if not ((args.fp16 or args.bf16) and
custom_kernel_constraint and
args.masked_softmax_fusion):
if args.rank == 0:
print('WARNING: constraints for invoking optimized'
' fused softmax kernel are not met. We default'
' back to unfused kernel invocations.', flush=True)
# Always build on rank zero first.
if torch.distributed.get_rank() == 0:
start_time = time.time()
print('> compiling and loading fused kernels ...', flush=True)
fused_kernels.load(args)
torch.distributed.barrier()
else:
torch.distributed.barrier()
fused_kernels.load(args)
# Simple barrier to make sure all ranks have passed the
# compilation phase successfully before moving on to the
# rest of the program. We think this might ensure that
# the lock is released.
torch.distributed.barrier()
if torch.distributed.get_rank() == 0:
print('>>> done with compiling and loading fused kernels. '
'Compilation time: {:.3f} seconds'.format(
time.time() - start_time), flush=True)
def _initialize_distributed():
"""Initialize torch.distributed and core model parallel."""
args = get_args()
device_count = torch.cuda.device_count()
if torch.distributed.is_initialized():
if args.rank == 0:
print('torch distributed is already initialized, '
'skipping initialization ...', flush=True)
args.rank = torch.distributed.get_rank()
args.world_size = torch.distributed.get_world_size()
else:
if args.rank == 0:
print('> initializing torch distributed ...', flush=True)
# Manually set the device ids.
if device_count > 0:
device = args.rank % device_count
if args.local_rank is not None:
assert args.local_rank == device, \
'expected local-rank to be the same as rank % device-count.'
else:
args.local_rank = device
torch.cuda.set_device(device)
# Call the init process
init_method = 'tcp://'
master_ip = os.getenv('MASTER_ADDR', 'localhost')
master_port = os.getenv('MASTER_PORT', '6000')
args.rank = int(os.getenv('RANK', '0'))
init_method += master_ip + ':' + master_port
torch.distributed.init_process_group(
backend=args.distributed_backend,
init_method=init_method,
world_size=args.world_size, rank=args.rank,
timeout=timedelta(minutes=args.distributed_timeout_minutes))
torch.distributed.barrier()
# Set the tensor model-parallel, pipeline model-parallel, and
# data-parallel communicators.
if device_count > 0:
if mpu.model_parallel_is_initialized():
print('model parallel is already initialized')
else:
mpu.initialize_model_parallel(args.tensor_model_parallel_size,
args.pipeline_model_parallel_size,
args.virtual_pipeline_model_parallel_size,
args.pipeline_model_parallel_split_rank)
if args.rank == 0:
print(f'> initialized tensor model parallel with size '
f'{mpu.get_tensor_model_parallel_world_size()}')
print(f'> initialized pipeline model parallel with size '
f'{mpu.get_pipeline_model_parallel_world_size()}')
def _init_autoresume():
"""Set autoresume start time."""
autoresume = get_adlr_autoresume()
if autoresume:
torch.distributed.barrier()
autoresume.init()
torch.distributed.barrier()
def _set_random_seed(seed_, data_parallel_random_init=False):
"""Set random seed for reproducability."""
if seed_ is not None and seed_ > 0:
# Ensure that different pipeline MP stages get different seeds.
seed = seed_ + (100 * mpu.get_pipeline_model_parallel_rank())
# Ensure different data parallel ranks get different seeds
if data_parallel_random_init:
seed = seed + (10 * mpu.get_data_parallel_rank())
random.seed(seed)
np.random.seed(seed)
torch.manual_seed(seed)
if torch.cuda.device_count() > 0:
tensor_parallel.model_parallel_cuda_manual_seed(seed)
else:
raise ValueError('Seed ({}) should be a positive integer.'.format(seed))
def write_args_to_tensorboard():
"""Write arguments to tensorboard."""
args = get_args()
writer = get_tensorboard_writer()
if writer:
for arg in vars(args):
writer.add_text(arg, str(getattr(args, arg)),
global_step=args.iteration)
def set_jit_fusion_options():
"""Set PyTorch JIT layer fusion options."""
# flags required to enable jit fusion kernels
TORCH_MAJOR = int(torch.__version__.split('.')[0])
TORCH_MINOR = int(torch.__version__.split('.')[1])
if (TORCH_MAJOR > 1) or (TORCH_MAJOR == 1 and TORCH_MINOR >= 10):
# nvfuser
torch._C._jit_set_profiling_executor(True)
torch._C._jit_set_profiling_mode(True)
torch._C._jit_override_can_fuse_on_cpu(False)
torch._C._jit_override_can_fuse_on_gpu(False)
torch._C._jit_set_texpr_fuser_enabled(False)
torch._C._jit_set_nvfuser_enabled(True)
torch._C._debug_set_autodiff_subgraph_inlining(False)
else:
# legacy pytorch fuser
torch._C._jit_set_profiling_mode(False)
torch._C._jit_set_profiling_executor(False)
torch._C._jit_override_can_fuse_on_cpu(True)
torch._C._jit_override_can_fuse_on_gpu(True)
_warmup_jit_function()
def _warmup_jit_function():
""" Compilie JIT functions before the main training steps """
args = get_args()
if args.bf16:
dtype = torch.bfloat16
elif args.fp16:
dtype = torch.float16
else:
dtype = torch.float32
# Warmup fused bias+gelu
bias = torch.rand(args.ffn_hidden_size // args.tensor_model_parallel_size,
dtype=dtype, device='cuda')
input = torch.rand((args.seq_length, args.micro_batch_size,
args.ffn_hidden_size // args.tensor_model_parallel_size),
dtype=dtype, device='cuda')
# Warmup JIT fusions with the input grad_enable state of both forward
# prop and recomputation
for bias_grad, input_grad in zip([True, True], [False, True]):
bias.requires_grad, input.requires_grad = bias_grad, input_grad
for _ in range(5):
output = bias_gelu(bias, input)
del bias, input, output
# Warmup fused bias+dropout+add
if args.sequence_parallel:
seq_length = args.seq_length // mpu.get_tensor_model_parallel_world_size()
else:
seq_length = args.seq_length
input = torch.rand((seq_length, args.micro_batch_size, args.hidden_size),
dtype=dtype, device='cuda')
residual = torch.rand((seq_length, args.micro_batch_size, args.hidden_size),
dtype=dtype, device='cuda')
bias = torch.rand((args.hidden_size), dtype=dtype, device='cuda').expand_as(residual)
dropout_rate = 0.1
# Warmup JIT fusions with the input grad_enable state of both forward
# prop and recomputation
for input_grad, bias_grad, residual_grad in zip([False, True], [True, True], [True, True]):
input.requires_grad = input_grad
bias.requires_grad = bias_grad
residual.requires_grad = residual_grad
for _ in range(5):
output = bias_dropout_add_fused_train(input, bias, residual, dropout_rate)
del bias, input, residual, output
torch.cuda.empty_cache()
megatron/memory.py 0 → 100644
View file @ d3dd8642
# Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
import torch
# A dictionary of all the memory buffers allocated.
_MEM_BUFFS = dict()
def allocate_mem_buff(name, numel, dtype, track_usage):
"""Allocate a memory buffer."""
assert name not in _MEM_BUFFS, \
'memory buffer {} already allocated.'.format(name)
_MEM_BUFFS[name] = MemoryBuffer(name, numel, dtype, track_usage)
return _MEM_BUFFS[name]
def get_mem_buff(name):
"""Get the memory buffer."""
return _MEM_BUFFS[name]
class MemoryBuffer:
"""Contiguous memory buffer.
Allocate a contiguous memory of type `dtype` and size `numel`. It is
used to reduce memory fragmentation.
Usage: After the allocation, the `_start` index is set tot the first
index of the memory. A memory chunk starting from `_start` index
can be `allocated` for an input tensor, with the elements of the
tensor being coppied. The buffer can be reused by resetting the
`_start` index.
"""
def __init__(self, name, numel, dtype, track_usage):
if torch.distributed.get_rank() == 0:
element_size = torch.tensor([], dtype=dtype).element_size()
print('> building the {} memory buffer with {} num elements '
'and {} dtype ({:.1f} MB)...'.format(
name, numel, dtype, numel*element_size/1024/1024),
flush=True)
self.name = name
self.numel = numel
self.dtype = dtype
self.data = torch.empty(self.numel,
dtype=self.dtype,
device=torch.cuda.current_device(),
requires_grad=False)
# Index tracking the start of the free memory.
self._start = 0
# Values used for tracking usage.
self.track_usage = track_usage
if self.track_usage:
self.in_use_value = 0.0
self.total_value = 0.0
def reset(self):
"""Reset the buffer start index to the beginning of the buffer."""
self._start = 0
def is_in_use(self):
"""Whether the current buffer hold on to any memory."""
return self._start > 0
def numel_in_use(self):
"""Return number of elements in use."""
return self._start
def add(self, tensor):
"""Allocate a chunk of memory from the buffer to tensor and copy
the values."""
assert tensor.dtype == self.dtype, \
'Input tensor type {} different from buffer type {}'.format(
tensor.dtype, self.dtype)
# Number of elements of the input tensor.
tensor_numel = torch.numel(tensor)
new_start = self._start + tensor_numel
assert new_start <= self.numel, \
'Not enough memory left in the buffer ({} > {})'.format(
tensor_numel, self.numel - self._start)
# New tensor is a view into the memory.
new_tensor = self.data[self._start:new_start]
self._start = new_start
new_tensor = new_tensor.view(tensor.shape)
new_tensor.copy_(tensor)
# Return a pointer to the new tensor.
return new_tensor
def get_data(self):
"""Return the data currently in use."""
if self.track_usage:
self.in_use_value += float(self._start)
self.total_value += float(self.numel)
return self.data[:self._start]
def print_average_usage(self):
"""Print memory usage average over time. We would like this value
to be as high as possible."""
assert self.track_usage, 'You need to enable track usage.'
if torch.distributed.get_rank() == 0:
print(' > usage of {} memory buffer: {:.2f} %'.format(
self.name, self.in_use_value * 100.0 / self.total_value),
flush=True)
class RingMemBuffer:
"""A ring of memory buffers."""
def __init__(self, name, num_buffers, numel, dtype, track_usage):
self.num_buffers = num_buffers
self.buffers = [
allocate_mem_buff(name+' {}'.format(i), numel, dtype, track_usage)
for i in range(num_buffers)]
self._index = -1
def get_next_buffer(self):
self._index += 1
self._index = self._index % self.num_buffers
buff = self.buffers[self._index]
assert not buff.is_in_use(), 'buffer is already in use.'
return buff
megatron/microbatches.py 0 → 100644
View file @ d3dd8642
# Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
"""Megatron number of micro-batches calculators."""
from abc import ABC
from abc import abstractmethod
def build_num_microbatches_calculator(args):
# Constant num micro-batches.
if args.rampup_batch_size is None:
num_microbatches_calculator = ConstantNumMicroBatches(
args.global_batch_size, args.micro_batch_size,
args.data_parallel_size)
if args.rank == 0:
print('setting number of micro-batches to constant {}'.format(
num_microbatches_calculator.get()), flush=True)
else:
assert len(args.rampup_batch_size) == 3, 'expected the following ' \
'format: --rampup-batch-size <start batch size> ' \
'<batch size incerement> <ramp-up samples>'
start_batch_size = int(args.rampup_batch_size[0])
batch_size_increment = int(args.rampup_batch_size[1])
ramup_samples = int(args.rampup_batch_size[2])
if args.rank == 0:
print('will use batch size rampup starting from global batch '
'size {} to global batch size {} with batch size increments '
'{} over {} samples.'.format(start_batch_size,
args.global_batch_size,
batch_size_increment,
ramup_samples), flush=True)
num_microbatches_calculator = RampupBatchsizeNumMicroBatches(
start_batch_size, batch_size_increment, ramup_samples,
args.global_batch_size, args.micro_batch_size,
args.data_parallel_size)
return num_microbatches_calculator
class NumMicroBatchesCalculator(ABC):
def __init__(self):
self.num_micro_batches = None
self.current_global_batch_size = None
def get(self):
return self.num_micro_batches
def get_current_global_batch_size(self):
return self.current_global_batch_size
@abstractmethod
def update(self, consumed_samples, consistency_check):
pass
class ConstantNumMicroBatches(NumMicroBatchesCalculator):
def __init__(self, global_batch_size, micro_batch_size, data_parallel_size):
micro_batch_times_data_parallel = micro_batch_size * \
data_parallel_size
assert global_batch_size % micro_batch_times_data_parallel == 0, \
'global batch size ({}) is not divisible by micro batch size ({})' \
' times data parallel size ({})'.format(global_batch_size,
micro_batch_size,
data_parallel_size)
self.num_micro_batches = global_batch_size // \
micro_batch_times_data_parallel
assert self.num_micro_batches >= 1
self.current_global_batch_size = global_batch_size
def update(self, consumed_samples, consistency_check):
pass
class RampupBatchsizeNumMicroBatches(NumMicroBatchesCalculator):
def __init__(self, start_batch_size, batch_size_increment, ramup_samples,
global_batch_size, micro_batch_size, data_parallel_size):
"""Batch size ramp up.
Over
steps = (global-batch-size - start-batch-size) / batch_size_increment
increment batch size from start-batch-size to global-batch-size using
rampup-samples / steps
samples.
Arguments:
start_batch_size: global batch size to start with
batch_size_increment: global batch size increments
ramup_samples: number of samples to use ramp up global
batch size from `start_batch_size` to `global_batch_size`
global_batch_size: global batch size post rampup
micro_batch_size: micro batch size
data_parallel_size: data parallel size.
"""
self.micro_batch_size = micro_batch_size
self.data_parallel_size = data_parallel_size
self.micro_batch_times_data_parallel_size = self.micro_batch_size * \
self.data_parallel_size
assert self.micro_batch_times_data_parallel_size > 0
assert start_batch_size > 0
self.start_batch_size = start_batch_size
assert global_batch_size > 0
self.global_batch_size = global_batch_size
diff_batch_size = self.global_batch_size - self.start_batch_size
assert diff_batch_size >= 0
assert batch_size_increment > 0
self.batch_size_increment = batch_size_increment
assert diff_batch_size % batch_size_increment == 0, 'expected ' \
'global batch size interval ({}) to be divisible by global batch ' \
'size increment ({})'.format(diff_batch_size, batch_size_increment)
num_increments = diff_batch_size // self.batch_size_increment
self.ramup_samples = ramup_samples
assert self.ramup_samples >= 0
self.rampup_samples_per_increment = self.ramup_samples / num_increments
# Initialize number of microbatches.
self.update(0, False)
def update(self, consumed_samples, consistency_check):
if consumed_samples > self.ramup_samples:
self.current_global_batch_size = self.global_batch_size
else:
steps = int(consumed_samples / self.rampup_samples_per_increment)
self.current_global_batch_size = self.start_batch_size + \
steps * self.batch_size_increment
assert self.current_global_batch_size <= self.global_batch_size
if consistency_check:
assert self.current_global_batch_size % \
self.micro_batch_times_data_parallel_size == 0, 'current global ' \
'batch size ({}) is not divisible by micro-batch-size ({}) times' \
'data parallel size ({})'.format(self.current_global_batch_size,
self.micro_batch_size,
self.data_parallel_size)
self.num_micro_batches = self.current_global_batch_size // \
self.micro_batch_times_data_parallel_size
megatron/model/__init__.py 0 → 100644
View file @ d3dd8642
# Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
from .fused_layer_norm import MixedFusedLayerNorm as LayerNorm
from apex.normalization import MixedFusedRMSNorm as RMSNorm
from .distributed import DistributedDataParallel
from .bert_model import BertModel
from .gpt_model import GPTModel
from .yuan_model import YuanModel
from .t5_model import T5Model
from .language_model import get_language_model
from .module import Float16Module
#from .yuan_hf_model import YuanForCausalLM
megatron/model/bert_model.py 0 → 100644
View file @ d3dd8642
# Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
"""BERT model."""
import torch
from megatron import get_args
from megatron.core import tensor_parallel
from megatron.model.enums import AttnMaskType
from megatron.model.language_model import parallel_lm_logits
from megatron.model.language_model import get_language_model
from megatron.model import LayerNorm
from megatron.model.utils import openai_gelu, erf_gelu
from megatron.model.utils import get_linear_layer
from megatron.model.utils import init_method_normal
from megatron.model.utils import scaled_init_method_normal
from .module import MegatronModule
def bert_extended_attention_mask(attention_mask):
# We create a 3D attention mask from a 2D tensor mask.
# [b, 1, s]
attention_mask_b1s = attention_mask.unsqueeze(1)
# [b, s, 1]
attention_mask_bs1 = attention_mask.unsqueeze(2)
# [b, s, s]
attention_mask_bss = attention_mask_b1s * attention_mask_bs1
# [b, 1, s, s]
extended_attention_mask = attention_mask_bss.unsqueeze(1)
# Convert attention mask to binary:
extended_attention_mask = (extended_attention_mask < 0.5)
return extended_attention_mask
def bert_position_ids(token_ids):
# Create position ids
seq_length = token_ids.size(1)
position_ids = torch.arange(seq_length, dtype=torch.long,
device=token_ids.device)
position_ids = position_ids.unsqueeze(0).expand_as(token_ids)
return position_ids
class BertLMHead(MegatronModule):
"""Masked LM head for Bert
Arguments:
config: TransformerConfig object
mpu_vocab_size: model parallel size of vocabulary.
hidden_size: hidden size
parallel_output: whether output logits being distributed or not.
"""
def __init__(self, mpu_vocab_size, hidden_size, config, parallel_output):
super().__init__(config=config)
args = get_args()
self.bias = torch.nn.Parameter(torch.zeros(mpu_vocab_size))
tensor_parallel.set_tensor_model_parallel_attributes(self.bias, True, 0, 1)
self.parallel_output = parallel_output
self.dense = get_linear_layer(hidden_size, hidden_size, config.init_method)
setattr(self.dense.weight, 'sequence_parallel', config.sequence_parallel)
setattr(self.dense.bias, 'sequence_parallel', config.sequence_parallel)
self.layernorm = LayerNorm(hidden_size,
eps=config.layernorm_epsilon,
sequence_parallel=config.sequence_parallel)
self.gelu = torch.nn.functional.gelu
if args.openai_gelu:
self.gelu = openai_gelu
elif args.onnx_safe:
self.gelu = erf_gelu
def forward(self, hidden_states, word_embeddings_weight):
hidden_states = self.dense(hidden_states)
hidden_states = self.gelu(hidden_states)
hidden_states = self.layernorm(hidden_states)
output = parallel_lm_logits(hidden_states,
word_embeddings_weight,
self.parallel_output,
bias=self.bias)
return output
def post_language_model_processing(lm_output, pooled_output,
lm_head, binary_head,
lm_labels,
logit_weights,
fp16_lm_cross_entropy):
# Output.
lm_logits = lm_head(
lm_output, logit_weights)
binary_logits = None
if binary_head is not None:
binary_logits = binary_head(pooled_output)
if lm_labels is None:
# [s b h] => [b s h]
return lm_logits.transpose(0,1).contiguous(), binary_logits
else:
# [b s] => [s b]
lm_labels = lm_labels.transpose(0,1).contiguous()
# lm_logits : [s, b, h] and lm_labels: [s, b]
if fp16_lm_cross_entropy:
assert lm_logits.dtype == torch.half
lm_loss = tensor_parallel.vocab_parallel_cross_entropy(lm_logits, lm_labels)
else:
lm_loss = tensor_parallel.vocab_parallel_cross_entropy(lm_logits.float(),
lm_labels)
# [s, b] => [b s]
lm_loss = lm_loss.transpose(0,1).contiguous()
return lm_loss, binary_logits
class BertModel(MegatronModule):
"""Bert Language model."""
def __init__(self,
config,
num_tokentypes=2,
add_binary_head=True,
parallel_output=True,
pre_process=True,
post_process=True):
super().__init__(config=config)
args = get_args()
# TODO this option is not yet implemented in BERT
assert args.untie_embeddings_and_output_weights is False
self.fp16_lm_cross_entropy = args.fp16_lm_cross_entropy
self.add_binary_head = add_binary_head
self.parallel_output = parallel_output
self.pre_process = pre_process
self.post_process = post_process
self.return_embeddings = args.output_bert_embeddings
if self.return_embeddings:
assert self.post_process and self.add_binary_head
self.language_model, self._language_model_key = get_language_model(
config=config,
num_tokentypes=num_tokentypes,
add_pooler=self.add_binary_head,
encoder_attn_mask_type=AttnMaskType.padding,
pre_process=self.pre_process,
post_process=self.post_process)
self.initialize_word_embeddings()
if self.post_process:
self.lm_head = BertLMHead(self.shared_embedding_or_output_weight().size(0), config.hidden_size,
config, parallel_output)
self._lm_head_key = 'lm_head'
self.binary_head = None
if self.add_binary_head:
self.binary_head = get_linear_layer(config.hidden_size, 2,
config.init_method)
self._binary_head_key = 'binary_head'
def set_input_tensor(self, input_tensor):
"""See megatron.model.transformer.set_input_tensor()"""
self.language_model.set_input_tensor(input_tensor)
def forward(self, bert_model_input, attention_mask,
tokentype_ids=None, lm_labels=None):
extended_attention_mask = bert_extended_attention_mask(attention_mask)
input_ids = bert_model_input
position_ids = bert_position_ids(input_ids)
lm_output = self.language_model(
input_ids,
position_ids,
extended_attention_mask,
tokentype_ids=tokentype_ids
)
if self.post_process and self.add_binary_head:
lm_output, pooled_output = lm_output
# Return pooled output (e.g., when computing Bert embeddings).
if self.return_embeddings:
# Sum attention mask.
embeddings = torch.transpose(lm_output, 0, 1)
masks = torch.sum(attention_mask, dim=1)
# Collect masked embeddings.
output = torch.zeros(
size=(embeddings.shape[0], embeddings.shape[2]),
dtype=torch.float32,
device=torch.cuda.current_device())
for i, (embedding, mask) in enumerate(zip(embeddings, masks)):
output[i, :] = torch.mean(embedding[1: mask - 1], dim=0)
return output
else:
pooled_output = None
if self.post_process:
return post_language_model_processing(lm_output, pooled_output,
self.lm_head, self.binary_head,
lm_labels,
self.shared_embedding_or_output_weight(),
self.fp16_lm_cross_entropy)
else:
return lm_output
def state_dict_for_save_checkpoint(self, prefix='', keep_vars=False):
"""For easy load when model is combined with other heads,
add an extra key."""
state_dict_ = {}
state_dict_[self._language_model_key] \
= self.language_model.state_dict_for_save_checkpoint(prefix=prefix,
keep_vars=keep_vars)
if self.post_process:
state_dict_[self._lm_head_key] \
= self.lm_head.state_dict_for_save_checkpoint(prefix=prefix,
keep_vars=keep_vars)
if self.post_process and self.add_binary_head:
state_dict_[self._binary_head_key] \
= self.binary_head.state_dict(prefix=prefix, keep_vars=keep_vars)
# Save word_embeddings.
if self.post_process and not self.pre_process:
state_dict_[self._word_embeddings_for_head_key] \
= self.word_embeddings.state_dict(prefix=prefix, keep_vars=keep_vars)
return state_dict_
def load_state_dict(self, state_dict, strict=True):
"""Customized load."""
self.language_model.load_state_dict(
state_dict[self._language_model_key], strict=strict)
if self.post_process:
self.lm_head.load_state_dict(
state_dict[self._lm_head_key], strict=strict)
if self.post_process and self.add_binary_head:
self.binary_head.load_state_dict(
state_dict[self._binary_head_key], strict=strict)
# Load word_embeddings.
if self.post_process and not self.pre_process:
self.word_embeddings.load_state_dict(
state_dict[self._word_embeddings_for_head_key], strict=strict)
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