Merge branch 'bfloat_fused_softmax' into 'main'

Bfloat fused softmax + fused layer norm

See merge request ADLR/megatron-lm!251

megatron/arguments.py

@@ -133,8 +133,7 @@ def parse_args(extra_args_provider=None, defaults={},
     if args.bf16:
         assert not args.fp16
         args.params_dtype = torch.bfloat16
-        # No fusion is support for bfloat for now
-        assert not args.masked_softmax_fusion
+        # Jitting fusion is not supported for bfloat for now
         assert not args.bias_gelu_fusion
         assert not args.bias_dropout_fusion
 

megatron/fused_kernels/__init__.py

@@ -82,12 +82,11 @@ def load(args):
     # Mixed precision fused layer norm.
     # =================================
 
-    if args.fp32_residual_connection:
-        extra_cuda_flags = ['-maxrregcount=50']
-        sources=[srcpath / 'layer_norm_cuda.cpp',
-                 srcpath / 'layer_norm_cuda_kernel.cu']
-        fused_mix_prec_layer_norm_cuda = _cpp_extention_load_helper(
-            "fused_mix_prec_layer_norm_cuda", sources, extra_cuda_flags)
+    extra_cuda_flags = ['-maxrregcount=50']
+    sources=[srcpath / 'layer_norm_cuda.cpp',
+             srcpath / 'layer_norm_cuda_kernel.cu']
+    fused_mix_prec_layer_norm_cuda = _cpp_extention_load_helper(
+        "fused_mix_prec_layer_norm_cuda", sources, extra_cuda_flags)
 
 
 def _get_cuda_bare_metal_version(cuda_dir):

megatron/fused_kernels/layer_norm_cuda.cpp

@@ -24,12 +24,12 @@
 #include "compat.h"
 
 namespace {
+
 void compute_n1_n2(
     at::Tensor input,
     at::IntArrayRef normalized_shape,
     int& n1,
-    int& n2)
-{
+    int& n2) {
     int idiff = input.ndimension() - normalized_shape.size();
     n2 = 1;
     for (int i = 0;  i < (int)normalized_shape.size();  ++i) {
@@ -118,39 +118,33 @@ void cuda_layer_norm(
 #define CHECK_CONTIGUOUS(x) TORCH_CHECK(x.is_contiguous(), #x " must be contiguous")
 #define CHECK_INPUT(x) CHECK_CUDA(x); CHECK_CONTIGUOUS(x)
 
-std::vector<at::Tensor> layer_norm(
-    at::Tensor input,
-    at::IntArrayRef normalized_shape,
-    double epsilon) {
-  CHECK_INPUT(input);
-  int n1,n2;
-  check_args(input,normalized_shape,n1,n2);
-  at::Tensor output = at::empty_like(input);
-  at::Tensor mean = at::empty({n1}, input.options().dtype(input.scalar_type()==at::ScalarType::Half ? at::ScalarType::Float : input.scalar_type()));
-  at::Tensor invvar = at::empty_like(mean);
-  cuda_layer_norm(&output,&mean,&invvar,&input,n1,n2,
-      normalized_shape,NULL,NULL,epsilon);
-  return {output, mean, invvar};
-}
 std::vector<at::Tensor> layer_norm_affine(
     at::Tensor input,
     at::IntArrayRef normalized_shape,
     at::Tensor gamma,
     at::Tensor beta,
     double epsilon) {
+  
   CHECK_INPUT(input);
   CHECK_INPUT(gamma);
   CHECK_INPUT(beta);
-  int n1,n2;
-  check_args(input,normalized_shape,gamma,beta,n1,n2);
-  at::Tensor output = at::empty_like(input, input.options().dtype(at::ScalarType::Half));
-  at::Tensor mean = at::empty({n1}, input.options().dtype(input.scalar_type()==at::ScalarType::Half ? at::ScalarType::Float : input.scalar_type()));
+  int n1, n2;
+  check_args(input, normalized_shape, gamma, beta, n1, n2);
+
+  at::Tensor output = at::empty_like(
+      input, gamma.options().dtype(gamma.scalar_type()));
+  at::Tensor mean = at::empty(
+      {n1}, input.options().dtype(at::ScalarType::Float));
   at::Tensor invvar = at::empty_like(mean);
-  cuda_layer_norm(&output,&mean,&invvar,&input,n1,n2,
-      normalized_shape,&gamma,&beta,epsilon);
+
+  cuda_layer_norm(&output, &mean, &invvar, &input, n1, n2,
+      normalized_shape, &gamma, &beta, epsilon);
+
   return {output, mean, invvar};
+
 }
 
+
 void cuda_layer_norm_gradient(
     at::Tensor* dout,
     at::Tensor* mean,
@@ -167,25 +161,6 @@ void cuda_layer_norm_gradient(
     at::Tensor* grad_beta
     );
 
-at::Tensor layer_norm_gradient(
-    at::Tensor dout,
-    at::Tensor mean,
-    at::Tensor invvar,
-    at::Tensor input,
-    at::IntArrayRef normalized_shape,
-    double epsilon) {
-  CHECK_INPUT(dout);
-  CHECK_INPUT(mean);
-  CHECK_INPUT(invvar);
-  CHECK_INPUT(input);
-  int n1,n2;
-  check_args(input,normalized_shape,n1,n2);
-  at::Tensor grad_input = at::empty_like(input);
-  cuda_layer_norm_gradient(&dout,&mean,&invvar,&input,n1,n2,
-      normalized_shape,NULL,NULL,epsilon,
-      &grad_input,NULL,NULL);
-  return grad_input;
-}
 std::vector<at::Tensor> layer_norm_gradient_affine(
     at::Tensor dout,
     at::Tensor mean,
@@ -195,26 +170,32 @@ std::vector<at::Tensor> layer_norm_gradient_affine(
     at::Tensor gamma,
     at::Tensor beta,
     double epsilon) {
+
   CHECK_INPUT(dout);
   CHECK_INPUT(mean);
   CHECK_INPUT(invvar);
   CHECK_INPUT(input);
   CHECK_INPUT(gamma);
   CHECK_INPUT(beta);
-  int n1,n2;
-  check_args(input,normalized_shape,gamma,beta,n1,n2);
+  int n1, n2;
+  check_args(input, normalized_shape, gamma, beta, n1, n2);
+
   at::Tensor grad_input = at::empty_like(input);
   at::Tensor grad_gamma = at::empty_like(gamma);
   at::Tensor grad_beta = at::empty_like(beta);
-  cuda_layer_norm_gradient(&dout,&mean,&invvar,&input,n1,n2,
-      normalized_shape,&gamma,&beta,epsilon,
-      &grad_input,&grad_gamma,&grad_beta);
+
+  cuda_layer_norm_gradient(&dout, &mean, &invvar, &input, n1, n2,
+      normalized_shape, &gamma, &beta, epsilon,
+      &grad_input, &grad_gamma, &grad_beta);
+
   return {grad_input, grad_gamma, grad_beta};
+
 }
 
+
 PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
-  m.def("forward_affine", &layer_norm_affine, "LayerNorm forward (CUDA)");
-  m.def("forward", &layer_norm, "LayerNorm forward (CUDA)");
-  m.def("backward_affine", &layer_norm_gradient_affine, "LayerNorm backward (CUDA)");
-  m.def("backward", &layer_norm_gradient, "LayerNorm backward (CUDA)");
+  m.def("forward_affine", &layer_norm_affine,
+	"LayerNorm forward (CUDA)");
+  m.def("backward_affine", &layer_norm_gradient_affine,
+	"LayerNorm backward (CUDA)");
 }

megatron/fused_kernels/layer_norm_cuda_kernel.cu

@@ -285,15 +285,6 @@ struct SharedMemory <float>
     }
 };
 
-template <>
-struct SharedMemory <double>
-{
-    __device__ double *getPointer()
-    {
-        extern __shared__ double s_double[];
-        return s_double;
-    }
-};
 }
 
 template<typename T, typename U, typename V> __global__
@@ -656,6 +647,9 @@ void cuComputeGradInput(
   }
 }
 
+
+
+
 template<typename T, typename U, typename V> 
 void HostApplyLayerNorm(
     V* output,
@@ -671,7 +665,8 @@ void HostApplyLayerNorm(
 {
     auto stream = at::cuda::getCurrentCUDAStream().stream();
     const dim3 threads(32,4,1);
-    const uint64_t maxGridY = at::cuda::getCurrentDeviceProperties()->maxGridSize[1];
+    const uint64_t maxGridY =
+      at::cuda::getCurrentDeviceProperties()->maxGridSize[1];
     const dim3 blocks(1, std::min((uint64_t)n1, maxGridY), 1);
     int nshared = 
         threads.y > 1 ? 
@@ -687,6 +682,7 @@ void HostApplyLayerNorm(
             gamma,beta);
 }
 
+
 void cuda_layer_norm(
     at::Tensor* output,
     at::Tensor* mean,
@@ -704,21 +700,21 @@ void cuda_layer_norm(
     double epsilon)
 {
     using namespace at;
-    DISPATCH_DOUBLE_FLOAT_AND_HALF(input->scalar_type(), 0, "layer_norm_cuda_kernel",
-        using accscalar_t = at::acc_type<scalar_t_0, true>;
-        using output_t = at::Half;
+    DISPATCH_FLOAT_HALF_AND_BFLOAT_INOUT_TYPES(
+        input->scalar_type(), output->scalar_type(), "cuda_layer_norm_kernel",
         HostApplyLayerNorm(
-        output->DATA_PTR<output_t>(),
-	    mean->DATA_PTR<accscalar_t>(),
-	    invvar->DATA_PTR<accscalar_t>(),
-	    input->DATA_PTR<scalar_t_0>(),
+	    output->DATA_PTR<scalar_t_out>(),
+	    mean->DATA_PTR<float>(),
+	    invvar->DATA_PTR<float>(),
+	    input->DATA_PTR<scalar_t_in>(),
 	    n1,n2,
 	    epsilon,
-	    gamma != NULL ? gamma->DATA_PTR<output_t>() : NULL,
-	    beta != NULL ? beta->DATA_PTR<output_t>() : NULL);
+	    gamma != NULL ? gamma->DATA_PTR<scalar_t_out>() : NULL,
+	    beta != NULL ? beta->DATA_PTR<scalar_t_out>() : NULL);
       )
 }
 
+
 template<typename T, typename U, typename V>
 void HostLayerNormGradient(
     const V* dout,
@@ -742,10 +738,12 @@ void HostLayerNormGradient(
       const int part_size = 16;
       const dim3 threads2(32,4,1);
       const dim3 blocks2((n2+threads2.x-1)/threads2.x,part_size,1);
-      const int nshared2_a = 2 * sizeof(U) * threads2.y * threads2.y * (threads2.x + 1);
+      const int nshared2_a = 2 * sizeof(U) * threads2.y * threads2.y *
+	(threads2.x + 1);
       const int nshared2_b = threads2.x * threads2.y * sizeof(U);
       const int nshared2 = nshared2_a > nshared2_b ? nshared2_a : nshared2_b;
-      at::Tensor part_grad_gamma = at::empty({part_size,n2}, input->options().dtype(input->scalar_type()==at::ScalarType::Half ? at::ScalarType::Float : input->scalar_type()));
+      at::Tensor part_grad_gamma = at::empty(
+	  {part_size,n2}, input->options().dtype(at::ScalarType::Float));
       at::Tensor part_grad_beta = at::empty_like(part_grad_gamma);
       cuComputePartGradGammaBeta<<<blocks2, threads2, nshared2, stream>>>(
 		      dout,
@@ -770,7 +768,8 @@ void HostLayerNormGradient(
     }
 
     // compute grad_input
-    const uint64_t maxGridY = at::cuda::getCurrentDeviceProperties()->maxGridSize[1];
+    const uint64_t maxGridY =
+      at::cuda::getCurrentDeviceProperties()->maxGridSize[1];
     const dim3 blocks1(1, std::min((uint64_t)n1, maxGridY), 1);
     const dim3 threads1(32,4,1);
     int nshared =
@@ -788,6 +787,7 @@ void HostLayerNormGradient(
             grad_input);
 }
 
+
 void cuda_layer_norm_gradient(
     at::Tensor* dout,
     at::Tensor* mean,
@@ -808,22 +808,22 @@ void cuda_layer_norm_gradient(
     at::Tensor* grad_beta)
 {
     using namespace at;
-    DISPATCH_FLOAT_AND_HALF(input->scalar_type(), 0, "cuComputeGradInput",
-        using accscalar_t = at::acc_type<scalar_t_0, true>;
-        using output_t = at::Half;
+    DISPATCH_FLOAT_HALF_AND_BFLOAT_INOUT_TYPES(
+        input->scalar_type(), gamma->scalar_type(),
+	"cuda_layer_norm_gradient_kernel",
         HostLayerNormGradient(
-	    dout->DATA_PTR<output_t>(),
-	    mean->DATA_PTR<accscalar_t>(),
-	    invvar->DATA_PTR<accscalar_t>(),
+	    dout->DATA_PTR<scalar_t_out>(),
+	    mean->DATA_PTR<float>(),
+	    invvar->DATA_PTR<float>(),
 	    input,
 	    n1,n2,
             // TMJ pass NULL argument for gamma, beta, grad_gamma and grad_beta
             // if gamma Tensor is NULL on input.
-	    gamma != NULL ? gamma->DATA_PTR<output_t>() : NULL,
-	    gamma != NULL ? beta->DATA_PTR<output_t>() : NULL,
+	    gamma != NULL ? gamma->DATA_PTR<scalar_t_out>() : NULL,
+	    gamma != NULL ? beta->DATA_PTR<scalar_t_out>() : NULL,
 	    epsilon,
-	    grad_input->DATA_PTR<scalar_t_0>(),
-	    gamma != NULL ? grad_gamma->DATA_PTR<output_t>() : NULL,
-	    gamma != NULL ? grad_beta->DATA_PTR<output_t>() : NULL);
+	    grad_input->DATA_PTR<scalar_t_in>(),
+	    gamma != NULL ? grad_gamma->DATA_PTR<scalar_t_out>() : NULL,
+	    gamma != NULL ? grad_beta->DATA_PTR<scalar_t_out>() : NULL);
       )
 }

megatron/fused_kernels/scaled_masked_softmax.cpp

@@ -37,8 +37,9 @@ torch::Tensor fwd(
     torch::Tensor const& mask,
     float scale_factor) {
   AT_ASSERTM(input.dim() == 4, "expected 4D tensor");
-  AT_ASSERTM(input.scalar_type() == at::ScalarType::Half, 
-      "Only HALF is supported");
+  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);
@@ -52,10 +53,12 @@ torch::Tensor bwd(
   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, 
-      "Only HALF is supported");
-  AT_ASSERTM(softmax_results.scalar_type() == at::ScalarType::Half, 
-      "Only HALF is supported");
+  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);
 }

megatron/fused_kernels/scaled_masked_softmax.h

@@ -30,10 +30,16 @@ template <typename Datatype, int ELEMENTS_PER_LDG>
 __device__ __inline__ void copy_vector(Datatype *dst, const Datatype *src);
 
 template <>
-__device__ __inline__ void copy_vector<__half, 1>(__half *dst, const __half *src) { *dst = *src; }
+__device__ __inline__ void copy_vector<c10::BFloat16, 1>(c10::BFloat16 *dst, const c10::BFloat16 *src) { *dst = *src; }
 
 template <>
-__device__ __inline__ void copy_vector<__half, 4>(__half *dst, const __half *src) { *((float2*) dst) = *((float2*) src); }
+__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; }

megatron/fused_kernels/scaled_masked_softmax_cuda.cu

@@ -22,6 +22,7 @@
 #include <ATen/cuda/CUDAContext.h>
 #include <torch/extension.h>
 #include "scaled_masked_softmax.h"
+#include "type_shim.h"
 
 namespace multihead_attn {
 namespace fused_softmax {
@@ -55,16 +56,20 @@ torch::Tensor fwd_cuda(
   void* mask_ptr = static_cast<void*>(mask.data_ptr());
   void* softmax_results_ptr = static_cast<void*>(softmax_results.data_ptr());
 
-  dispatch_scaled_masked_softmax_forward<half, half, float>(
-      reinterpret_cast<half*>(softmax_results_ptr),
-      reinterpret_cast<const half*>(input_ptr),
-      reinterpret_cast<const uint8_t*>(mask_ptr),
-      scale_factor,
-      query_seq_len,
-      key_seq_len,
-      batches,
-      attn_heads,
-      pad_batches);
+  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;
 }
 
@@ -85,15 +90,19 @@ torch::Tensor bwd_cuda(
   void* output_grads_ptr = static_cast<void*>(output_grads.data_ptr());
 
   //Softmax Grad
-  dispatch_scaled_masked_softmax_backward<half, half, float>(
-      reinterpret_cast<half*>(output_grads_ptr), 
-      reinterpret_cast<half*>(output_grads_ptr), 
-      reinterpret_cast<half const*>(softmax_results.data_ptr()),
-      scale_factor,
-      query_seq_len,
-      key_seq_len,
-      batches,
-      attn_heads);
+  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

@@ -33,8 +33,9 @@ torch::Tensor bwd_cuda(
 
 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, 
-      "Only HALF is supported");
+  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);
 }
@@ -47,10 +48,12 @@ torch::Tensor bwd(
   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, 
-      "Only HALF is supported");
-  AT_ASSERTM(softmax_results.scalar_type() == at::ScalarType::Half, 
-      "Only HALF is supported");
+  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);
 }
@@ -61,7 +64,7 @@ torch::Tensor bwd(
 
 PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
   m.def("forward", 
-        &multihead_attn::fused_softmax::scaled_upper_triang_masked_softmax::fwd, 
+        &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,

megatron/fused_kernels/scaled_upper_triang_masked_softmax.h

@@ -21,7 +21,6 @@
 #include <cfloat>
 #include <limits>
 #include <stdint.h>
-#include <cuda_fp16.h>
 #include <c10/macros/Macros.h>
 
 namespace {
@@ -30,10 +29,16 @@ template <typename Datatype, int ELEMENTS_PER_LDG>
 __device__ __inline__ void copy_vector(Datatype *dst, const Datatype *src);
 
 template <>
-__device__ __inline__ void copy_vector<__half, 1>(__half *dst, const __half *src) { *dst = *src; }
+__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<__half, 4>(__half *dst, const __half *src) { *((float2*) dst) = *((float2*) src); }
+__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; }
@@ -45,10 +50,16 @@ template <typename Datatype, int ELEMENTS_PER_LDG>
 __device__ __inline__ void copy_zero_vector(Datatype *dst);
 
 template <>
-__device__ __inline__ void copy_zero_vector<__half, 1>(__half *dst) { *dst = 0.0; }
+__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<__half, 4>(__half *dst) { *((float2*) dst) = make_float2(0.0f, 0.0f); }
+__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) {

megatron/fused_kernels/scaled_upper_triang_masked_softmax_cuda.cu

@@ -22,6 +22,7 @@
 #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 {
@@ -45,15 +46,20 @@ torch::Tensor fwd_cuda(
   void* input_ptr = static_cast<void*>(input.data_ptr());
   void* softmax_results_ptr = static_cast<void*>(softmax_results.data_ptr());
 
-  dispatch_scaled_upper_triang_masked_softmax_forward<half, half, float>(
-      reinterpret_cast<half*>(softmax_results_ptr),
-      reinterpret_cast<const half*>(input_ptr),
-      scale_factor,
-      seq_len,
-      seq_len,
-      attn_batches);
+  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_, 
@@ -71,14 +77,18 @@ torch::Tensor bwd_cuda(
   void* output_grads_ptr = static_cast<void*>(output_grads.data_ptr());
 
   //Softmax Grad
-  dispatch_scaled_upper_triang_masked_softmax_backward<half, half, float>(
-      reinterpret_cast<half*>(output_grads_ptr), 
-      reinterpret_cast<half*>(output_grads_ptr), 
-      reinterpret_cast<half const*>(softmax_results.data_ptr()),
-      scale_factor,
-      seq_len,
-      seq_len,
-      attn_batches);
+  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/type_shim.h

@@ -14,214 +14,78 @@
  * limitations under the License.
  */
 
-/*This code is copied fron NVIDIA apex:
- *     https://github.com/NVIDIA/apex
- *     with minor changes. */
 
 #include <ATen/ATen.h>
 #include "compat.h"
 
-// Forward/backward compatiblity hack around
-// https://github.com/pytorch/pytorch/commit/3aeb78079bcd68282fe9117088e138b77318e288
-// pending more future-proof guidance from upstream.
-// struct TypeShim
-// {
-//   const at::Type& payload;
-//   TypeShim(const at::Type& type) : payload(type) {}
-//   // Enable trivial conversion to a const at::Type& for pre-3aeb78
-//   operator const at::Type&(){ return payload; };
-//   // Enable dispatch switch statements to take *this directly for  post-3aeb78
-//   //operator at::ScalarType(){ return payload.; };
-// };
 
-#define DISPATCH_FLOAT_AND_HALF(TYPE, LEVEL, NAME, ...) \
-  switch(TYPE) \
-  { \
-    case at::ScalarType::Float: \
-    { \
-      using scalar_t_##LEVEL = float; \
-      __VA_ARGS__; \
-      break; \
-    } \
-    case at::ScalarType::Half: \
-    { \
-      using scalar_t_##LEVEL = at::Half; \
-      __VA_ARGS__; \
-      break; \
-    } \
-    default: \
-      AT_ERROR(#NAME, " not implemented for '", toString(TYPE), "'");  \
-  }
+#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_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), "'");	\
+    }
 
-
-#define DISPATCH_FLOAT_HALF_AND_BYTE(TYPE, LEVEL, NAME, ...) \
-  switch(TYPE) \
-  { \
-    case at::ScalarType::Float: \
-    { \
-      using scalar_t_##LEVEL = float; \
-      __VA_ARGS__; \
-      break; \
-    } \
-    case at::ScalarType::Half: \
-    { \
-      using scalar_t_##LEVEL = at::Half; \
-      __VA_ARGS__; \
-      break; \
-    } \
-    case at::ScalarType::Byte: \
-    { \
-      using scalar_t_##LEVEL = uint8_t; \
-      __VA_ARGS__; \
-      break; \
-    } \
-    default: \
-      AT_ERROR(#NAME, " not implemented for '", toString(TYPE), "'");  \
-  }
-
-
-#define DISPATCH_DOUBLE_FLOAT_AND_HALF(TYPE, LEVEL, NAME, ...) \
-  switch(TYPE) \
-  { \
-    case at::ScalarType::Double: \
-    { \
-      using scalar_t_##LEVEL = double; \
-      __VA_ARGS__; \
-      break; \
-    } \
-    case at::ScalarType::Float: \
-    { \
-      using scalar_t_##LEVEL = float; \
-      __VA_ARGS__; \
-      break; \
-    } \
-    case at::ScalarType::Half: \
-    { \
-      using scalar_t_##LEVEL = at::Half; \
-      __VA_ARGS__; \
-      break; \
-    } \
-    default: \
-      AT_ERROR(#NAME, " not implemented for '", toString(TYPE), "'");  \
-  }
-
-
-  #define DISPATCH_DOUBLE_AND_FLOAT(TYPE, LEVEL, NAME, ...) \
-  switch(TYPE) \
-  { \
-    case at::ScalarType::Double: \
-    { \
-      using scalar_t_##LEVEL = double; \
-      __VA_ARGS__; \
-      break; \
-    } \
-    case at::ScalarType::Float: \
-    { \
-      using scalar_t_##LEVEL = float; \
-      __VA_ARGS__; \
-      break; \
-    } \
-    default: \
-      AT_ERROR(#NAME, " not implemented for '", toString(TYPE), "'");  \
-  }
-
-
-template<typename T>
-__device__ __forceinline__ T reduce_block_into_lanes
-  (T *x,
-   T val,
-   int lanes=1,
-   bool share_result=false) // lanes is intended to be <= 32.
-{
-  int tid = threadIdx.x + threadIdx.y*blockDim.x;
-  int blockSize = blockDim.x*blockDim.y; // blockSize is intended to be a multiple of 32.
-
-  if(blockSize >= 64)
-  {
-    x[tid] = val;
-    __syncthreads();
-  }
-
-  #pragma unroll
-  for(int i = (blockSize >> 1); i >= 64; i >>= 1)
-  {
-    if(tid < i)
-      x[tid] = x[tid] + x[tid+i];
-    __syncthreads();
-  }
-
-  T final;
-
-  if(tid < 32)
-  {
-    if(blockSize >= 64)
-      final = x[tid] + x[tid+32];
-    else
-      final = val;
-    // __SYNCWARP();
-
-    #pragma unroll
-    for(int i = 16; i >= lanes; i >>= 1)
-      final = final + __shfl_down_sync(0xffffffff, final, i);
-  }
-
-  if(share_result)
-  {
-    if(tid < lanes)
-      x[tid] = final; // EpilogueOp
-    // Make sure the smem result is visible to all warps.
-    __syncthreads();
-  }
-
-  return final;
-}
-
-template<typename T>
-__device__ __forceinline__ T reduce_block_into_lanes_max_op
-  (T *x,
-   T val,
-   int lanes=1,
-   bool share_result=false) // lanes is intended to be <= 32.
-{
-  int tid = threadIdx.x + threadIdx.y*blockDim.x;
-  int blockSize = blockDim.x*blockDim.y; // blockSize is intended to be a multiple of 32.
-
-  if(blockSize >= 64)
-  {
-    x[tid] = val;
-    __syncthreads();
-  }
-
-  #pragma unroll
-  for(int i = (blockSize >> 1); i >= 64; i >>= 1)
-  {
-    if(tid < i)
-      x[tid] = fmaxf(fabsf(x[tid]), fabsf(x[tid+i]));
-    __syncthreads();
-  }
-
-  T final;
-
-  if(tid < 32)
-  {
-    if(blockSize >= 64)
-      final = fmaxf(fabsf(x[tid]), fabsf(x[tid+32]));
-    else
-      final = val;
-    // __SYNCWARP();
-
-    #pragma unroll
-    for(int i = 16; i >= lanes; i >>= 1)
-      final = fmaxf(fabsf(final), fabsf(__shfl_down_sync(0xffffffff, final, i)));
-  }
-
-  if(share_result)
-  {
-    if(tid < lanes)
-      x[tid] = final; // EpilogueOp
-    // Make sure the smem result is visible to all warps.
-    __syncthreads();
-  }
-
-  return final;
-}

megatron/model/__init__.py

@@ -13,23 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-_LAYER_NORM = None
-
-
-def import_layernorm(fp32_residual_connection, bf16):
-
-    global _LAYER_NORM
-    if not _LAYER_NORM:
-        if bf16:
-            from torch.nn import LayerNorm
-        elif fp32_residual_connection:
-            from .fused_layer_norm import MixedFusedLayerNorm as LayerNorm
-        else:
-            from apex.normalization.fused_layer_norm import FusedLayerNorm as LayerNorm
-        _LAYER_NORM = LayerNorm
-            
-    return _LAYER_NORM
-
+from .fused_layer_norm import MixedFusedLayerNorm as LayerNorm
 
 from .distributed import *
 from .bert_model import (BertModel,

megatron/model/bert_model.py

@@ -22,7 +22,7 @@ from megatron import mpu
 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 import_layernorm
+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
@@ -78,7 +78,6 @@ class BertLMHead(MegatronModule):
         self.parallel_output = parallel_output
 
         self.dense = get_linear_layer(hidden_size, hidden_size, init_method)
-        LayerNorm = import_layernorm(args.fp32_residual_connection, args.bf16)
         self.layernorm = LayerNorm(hidden_size, eps=layernorm_epsilon)
         self.gelu = torch.nn.functional.gelu
         if args.openai_gelu:

megatron/model/fused_layer_norm.py

@@ -15,29 +15,23 @@
 
 """This code is copied fron NVIDIA apex:
       https://github.com/NVIDIA/apex
-   with minor changes. """
+   with some changes. """
 
-
-import math
-import torch
 import numbers
+import torch
 from torch.nn.parameter import Parameter
 from torch.nn import init
-from torch.nn import functional as F
 import importlib
 
-global fused_layer_norm_cuda
-fused_layer_norm_cuda = None
 global fused_mix_prec_layer_norm_cuda
 fused_mix_prec_layer_norm_cuda = None
 
+
 class FusedLayerNormAffineFunction(torch.autograd.Function):
 
   @staticmethod
   def forward(ctx, input, weight, bias, normalized_shape, eps):
-    global fused_mix_prec_layer_norm_cuda
-    if fused_mix_prec_layer_norm_cuda is None:
-        fused_mix_prec_layer_norm_cuda = importlib.import_module("fused_mix_prec_layer_norm_cuda")
+
     ctx.normalized_shape = normalized_shape
     ctx.eps = eps
     input_ = input.contiguous()
@@ -46,134 +40,51 @@ class FusedLayerNormAffineFunction(torch.autograd.Function):
     output, mean, invvar = fused_mix_prec_layer_norm_cuda.forward_affine(
         input_, ctx.normalized_shape, weight_, bias_, ctx.eps)
     ctx.save_for_backward(input_, weight_, bias_, mean, invvar)
+
     return output
 
+
   @staticmethod
   def backward(ctx, grad_output):
+
     input_, weight_, bias_, mean, invvar = ctx.saved_tensors
     grad_input = grad_weight = grad_bias = None
-    grad_input, grad_weight, grad_bias = fused_mix_prec_layer_norm_cuda.backward_affine(
+    grad_input, grad_weight, grad_bias \
+      = fused_mix_prec_layer_norm_cuda.backward_affine(
         grad_output.contiguous(), mean, invvar,
         input_, ctx.normalized_shape,
         weight_, bias_, ctx.eps)
-    return grad_input, grad_weight, grad_bias, None, None
-
-class FusedLayerNormFunction(torch.autograd.Function):
 
-  @staticmethod
-  def forward(ctx, input, normalized_shape, eps):
-    global fused_layer_norm_cuda
-    if fused_layer_norm_cuda is None:
-        fused_layer_norm_cuda = importlib.import_module("fused_layer_norm_cuda")
-    ctx.normalized_shape = normalized_shape
-    ctx.eps = eps
-    input_ = input.contiguous()
-    output, mean, invvar = fused_layer_norm_cuda.forward(
-        input_, ctx.normalized_shape, ctx.eps)
-    ctx.save_for_backward(input_, mean, invvar)
-    return output
-
-  @staticmethod
-  def backward(ctx, grad_output):
-    input_, mean, invvar = ctx.saved_tensors
-    grad_input = None
-    grad_input = fused_layer_norm_cuda.backward(
-        grad_output.contiguous(), mean, invvar,
-        input_, ctx.normalized_shape,
-        ctx.eps)
-    return grad_input, None, None
+    return grad_input, grad_weight, grad_bias, None, None
 
-def fused_layer_norm_affine(input, normalized_shape, weight, bias, eps=1e-6):
-    return FusedLayerNormAffineFunction.apply(input, weight, bias, normalized_shape, eps)
 
-def fused_layer_norm(input, normalized_shape, eps=1e-6):
-    return FusedLayerNormFunction.apply(input, normalized_shape, eps)
 
 class MixedFusedLayerNorm(torch.nn.Module):
-    r"""Applies Layer Normalization over a mini-batch of inputs as described in
-    the paper `Layer Normalization`_ .
-    Currently only runs on cuda() tensors.
-    .. math::
-        y = \frac{x - \mathrm{E}[x]}{ \sqrt{\mathrm{Var}[x] + \epsilon}} * \gamma + \beta
-    The mean and standard-deviation are calculated separately over the last
-    certain number dimensions which have to be of the shape specified by
-    :attr:`normalized_shape`.
-    :math:`\gamma` and :math:`\beta` are learnable affine transform parameters of
-    :attr:`normalized_shape` if :attr:`elementwise_affine` is ``True``.
-    .. note::
-        Unlike Batch Normalization and Instance Normalization, which applies
-        scalar scale and bias for each entire channel/plane with the
-        :attr:`affine` option, Layer Normalization applies per-element scale and
-        bias with :attr:`elementwise_affine`.
-    This layer uses statistics computed from input data in both training and
-    evaluation modes.
-    Args:
-        normalized_shape (int or list or torch.Size): input shape from an expected input
-            of size
-            .. math::
-                [* \times \text{normalized}\_\text{shape}[0] \times \text{normalized}\_\text{shape}[1]
-                    \times \ldots \times \text{normalized}\_\text{shape}[-1]]
-            If a single integer is used, it is treated as a singleton list, and this module will
-            normalize over the last dimension which is expected to be of that specific size.
-        eps: a value added to the denominator for numerical stability. Default: 1e-5
-        elementwise_affine: a boolean value that when set to ``True``, this module
-            has learnable per-element affine parameters initialized to ones (for weights)
-            and zeros (for biases). Default: ``True``.
-    Shape:
-        - Input: :math:`(N, *)`
-        - Output: :math:`(N, *)` (same shape as input)
-    Examples::
-        >>> input = torch.randn(20, 5, 10, 10)
-        >>> # With Learnable Parameters
-        >>> m = apex.normalization.FusedLayerNorm(input.size()[1:])
-        >>> # Without Learnable Parameters
-        >>> m = apex.normalization.FusedLayerNorm(input.size()[1:], elementwise_affine=False)
-        >>> # Normalize over last two dimensions
-        >>> m = apex.normalization.FusedLayerNorm([10, 10])
-        >>> # Normalize over last dimension of size 10
-        >>> m = apex.normalization.FusedLayerNorm(10)
-        >>> # Activating the module
-        >>> output = m(input)
-    .. _`Layer Normalization`: https://arxiv.org/abs/1607.06450
-    """
-    def __init__(self, normalized_shape, eps=1e-5, elementwise_affine=True):
+
+  def __init__(self, normalized_shape, eps=1e-5):
         super(MixedFusedLayerNorm, self).__init__()
 
-        global fused_layer_norm_cuda
-        fused_layer_norm_cuda = importlib.import_module("fused_layer_norm_cuda")
         global fused_mix_prec_layer_norm_cuda
-        fused_mix_prec_layer_norm_cuda = importlib.import_module("fused_mix_prec_layer_norm_cuda")
-
+        fused_mix_prec_layer_norm_cuda = importlib.import_module(
+          "fused_mix_prec_layer_norm_cuda")
 
         if isinstance(normalized_shape, numbers.Integral):
             normalized_shape = (normalized_shape,)
         self.normalized_shape = torch.Size(normalized_shape)
         self.eps = eps
-        self.elementwise_affine = elementwise_affine
-        if self.elementwise_affine:
-            self.weight = Parameter(torch.Tensor(*normalized_shape))
-            self.bias = Parameter(torch.Tensor(*normalized_shape))
-        else:
-            self.register_parameter('weight', None)
-            self.register_parameter('bias', None)
+        self.weight = Parameter(torch.Tensor(*normalized_shape))
+        self.bias = Parameter(torch.Tensor(*normalized_shape))
         self.reset_parameters()
 
-    def reset_parameters(self):
-        if self.elementwise_affine:
-            init.ones_(self.weight)
-            init.zeros_(self.bias)
-
-    def forward(self, input):
-        if not input.is_cuda:
-            return  F.layer_norm(
-                input, self.normalized_shape, self.weight, self.bias, self.eps)
-        
-        if self.elementwise_affine:
-          return FusedLayerNormAffineFunction.apply(
-              input, self.weight, self.bias, self.normalized_shape,self.eps)
-        else:
-          return FusedLayerNormFunction.apply(input, self.normalized_shape, self.eps) 
-
-    def extra_repr(self):
-        return '{normalized_shape}, eps={eps}, ' \
-            'elementwise_affine={elementwise_affine}'.format(**self.__dict__)
+
+  def reset_parameters(self):
+
+    init.ones_(self.weight)
+    init.zeros_(self.bias)
+
+
+  def forward(self, input):
+
+    return FusedLayerNormAffineFunction.apply(
+      input, self.weight, self.bias, self.normalized_shape,self.eps)
+

megatron/model/fused_softmax.py

@@ -96,6 +96,7 @@ class FusedScaleMaskSoftmax(torch.nn.Module):
     def __init__(
         self,
         input_in_fp16,
+        input_in_bf16,
         attn_mask_type,
         scaled_masked_softmax_fusion,
         mask_func,
@@ -104,6 +105,10 @@ class FusedScaleMaskSoftmax(torch.nn.Module):
     ):
         super(FusedScaleMaskSoftmax, self).__init__()
         self.input_in_fp16 = input_in_fp16
+        self.input_in_bf16 = input_in_bf16
+        assert not (self.input_in_fp16 and self.input_in_bf16),\
+            'both fp16 and bf16 flags cannot be active at the same time.'
+        self.input_in_float16 = self.input_in_fp16 or self.input_in_bf16
         self.attn_mask_type = attn_mask_type
         self.scaled_masked_softmax_fusion = scaled_masked_softmax_fusion
         self.mask_func = mask_func
@@ -128,8 +133,8 @@ class FusedScaleMaskSoftmax(torch.nn.Module):
             query_seq_len % 4 == 0 and attn_batch_size % 4 == 0
 
         # invoke custom kernel
-        if self.input_in_fp16 and mask is not None and \
-           custom_kernel_constraint and self.scaled_masked_softmax_fusion:
+        if self.input_in_float16 and mask is not None and \
+            custom_kernel_constraint and self.scaled_masked_softmax_fusion:
             scale = self.scale if self.scale is not None else 1.0
 
             if self.attn_mask_type == AttnMaskType.causal:
@@ -142,7 +147,7 @@ class FusedScaleMaskSoftmax(torch.nn.Module):
                 assert self.attn_mask_type == AttnMaskType.padding
                 probs = ScaledMaskedSoftmax.apply(input, mask, scale)
         else:
-            if self.input_in_fp16 and self.softmax_in_fp32:
+            if self.input_in_float16 and self.softmax_in_fp32:
                 input = input.float()
 
             if self.scale is not None:
@@ -150,7 +155,10 @@ class FusedScaleMaskSoftmax(torch.nn.Module):
             mask_output = self.mask_func(input, mask) if mask is not None else input
             probs = torch.nn.Softmax(dim=-1)(mask_output)
 
-            if self.input_in_fp16 and self.softmax_in_fp32:
-                probs = probs.half()
+            if self.input_in_float16 and self.softmax_in_fp32:
+                if self.input_in_fp16:
+                    probs = probs.half()
+                else:
+                    probs = probs.bfloat16()
 
         return probs

megatron/model/transformer.py

@@ -22,7 +22,7 @@ from megatron import get_args
 from megatron import mpu
 from .module import MegatronModule
 from megatron.model.enums import AttnMaskType, LayerType, AttnType
-from megatron.model import import_layernorm
+from megatron.model import LayerNorm
 from megatron.model.fused_softmax import FusedScaleMaskSoftmax
 from megatron.model.fused_bias_gelu import bias_gelu_impl
 from megatron.model.utils import attention_mask_func, openai_gelu, erf_gelu
@@ -116,6 +116,7 @@ class ParallelAttention(MegatronModule):
         super(ParallelAttention, self).__init__()
         args = get_args()
         self.fp16 = args.fp16
+        self.bf16 = args.bf16
 
         self.apply_query_key_layer_scaling = args.apply_query_key_layer_scaling
         self.attention_softmax_in_fp32 = args.attention_softmax_in_fp32
@@ -164,7 +165,7 @@ class ParallelAttention(MegatronModule):
             self.norm_factor *= coeff
 
         self.scale_mask_softmax = FusedScaleMaskSoftmax(
-            self.fp16,
+            self.fp16, self.bf16,
             self.attn_mask_type,
             args.masked_softmax_fusion,
             attention_mask_func,
@@ -401,7 +402,6 @@ class ParallelTransformerLayer(MegatronModule):
         self.fp32_residual_connection = args.fp32_residual_connection
 
         # Layernorm on the input data.
-        LayerNorm = import_layernorm(self.fp32_residual_connection, self.bf16)
         self.input_layernorm = LayerNorm(
             args.hidden_size,
             eps=args.layernorm_epsilon)
@@ -443,8 +443,6 @@ class ParallelTransformerLayer(MegatronModule):
 
         # Layer norm at the beginning of the transformer layer.
         layernorm_output = self.input_layernorm(hidden_states)
-        if self.bf16 and self.fp32_residual_connection:
-            layernorm_output = layernorm_output.bfloat16()
         # Self attention.
         attention_output, attention_bias = \
             self.self_attention(layernorm_output,
@@ -483,8 +481,6 @@ class ParallelTransformerLayer(MegatronModule):
 
         # Layer norm post the self attention.
         layernorm_output = self.post_attention_layernorm(layernorm_input)
-        if self.bf16 and self.fp32_residual_connection:
-            layernorm_output = layernorm_output.bfloat16()
 
         if self.layer_type == LayerType.decoder:
             attention_output, attention_bias = \
@@ -507,8 +503,6 @@ class ParallelTransformerLayer(MegatronModule):
 
             # Layer norm post the decoder attention
             layernorm_output = self.post_inter_attention_layernorm(layernorm_input)
-            if self.bf16 and self.fp32_residual_connection:
-                layernorm_output = layernorm_output.bfloat16()
 
         # MLP.
         mlp_output, mlp_bias = self.mlp(layernorm_output)
@@ -588,8 +582,6 @@ class ParallelTransformer(MegatronModule):
 
         if mpu.is_pipeline_last_stage():
             # Final layer norm before output.
-            LayerNorm = import_layernorm(self.fp32_residual_connection,
-                                         self.bf16)
             self.final_layernorm = LayerNorm(
                 args.hidden_size,
                 eps=args.layernorm_epsilon)
@@ -676,8 +668,6 @@ class ParallelTransformer(MegatronModule):
             # Reverting data format change [s b h] --> [b s h].
             hidden_states = hidden_states.transpose(0, 1).contiguous()
             output = self.final_layernorm(hidden_states)
-            if self.bf16 and self.fp32_residual_connection:
-                output = output.bfloat16()
         else:
             output = hidden_states
         if get_key_value:

megatron/optimizer/__init__.py

@@ -17,7 +17,7 @@ from apex.optimizers import FusedAdam as Adam
 from apex.optimizers import FusedSGD as SGD
 
 from megatron import get_args
-from megatron.model import import_layernorm
+from megatron.model import LayerNorm
 
 from .grad_scaler import ConstantGradScaler, DynamicGradScaler
 from .optimizer import Float16OptimizerWithFloat16Params, FP32Optimizer
@@ -27,8 +27,6 @@ def _get_params_for_weight_decay_optimization(modules):
     """Divide params into with-weight-decay and without-weight-decay groups.
     Layernorms and baises will have no weight decay but the rest will.
     """
-    args = get_args()
-    LayerNorm = import_layernorm(args.fp32_residual_connection, args.bf16)
 
     weight_decay_params = {'params': []}
     no_weight_decay_params = {'params': [], 'weight_decay': 0.0}

megatron/training.py

@@ -224,16 +224,6 @@ def get_model(model_provider_func):
     # Fp16 conversion.
     if args.fp16 or args.bf16:
         model = [Float16Module(model_module, args) for model_module in model]
-        # For now, the layer norm does not support input float32 and outut bf16.
-        # For this, we move layernorm parameters to fp32 and cast output of the
-        # layernorm operation back to bf16.
-        if args.bf16 and args.fp32_residual_connection:
-            from megatron.model import import_layernorm
-            LayerNorm = import_layernorm(args.fp32_residual_connection, args.bf16)
-            for model_ in model:
-                for module_ in model_.modules():
-                    if isinstance(module_, LayerNorm):
-                        module_.float()
 
     if args.DDP_impl == 'torch':
         i = torch.cuda.current_device()