Merge branch 'main' into checkpoint_util

megatron/fused_kernels/scaled_softmax_cuda.cu

+/* coding=utf-8
+ * Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#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/global_vars.py

@@ -21,6 +21,7 @@ import time
 
 import torch
 
+from megatron import dist_signal_handler
 from megatron.tokenizer import build_tokenizer
 from .arguments import parse_args
 from .microbatches import build_num_microbatches_calculator
@@ -31,6 +32,7 @@ _GLOBAL_TOKENIZER = None
 _GLOBAL_TENSORBOARD_WRITER = None
 _GLOBAL_ADLR_AUTORESUME = None
 _GLOBAL_TIMERS = None
+_GLOBAL_SIGNAL_HANDLER = None
 
 
 def get_args():
@@ -75,6 +77,14 @@ def get_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(extra_args_provider=None, args_defaults={},
                          ignore_unknown_args=False, parse_args=True):
@@ -93,10 +103,15 @@ def set_global_variables(extra_args_provider=None, args_defaults={},
     _set_adlr_autoresume(args)
     _set_timers()
 
+    if args.exit_signal_handler:
+        _set_signal_handler()
+    
+
 def set_args(args):
     global _GLOBAL_ARGS
     _GLOBAL_ARGS = args
 
+
 def _parse_args(extra_args_provider=None, defaults={},
                 ignore_unknown_args=False):
     """Parse entire arguments."""

megatron/initialize.py

@@ -62,7 +62,7 @@ def initialize_megatron(extra_args_provider=None, args_defaults={},
         # Random seeds for reproducibility.
         if args.rank == 0:
             print('> setting random seeds to {} ...'.format(args.seed))
-        _set_random_seed(args.seed)
+        _set_random_seed(args.seed, args.data_parallel_random_init)
 
     # Set pytorch JIT layer fusion options.
     _set_jit_fusion_options()
@@ -118,7 +118,7 @@ def _compile_dependencies():
         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 <=2048 and \
+    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
@@ -180,7 +180,7 @@ def _initialize_distributed():
     torch.distributed.init_process_group(
         backend=args.distributed_backend,
         world_size=args.world_size, rank=args.rank,
-        timeout=timedelta(days=7))
+        timeout=timedelta(minutes=10))
 
     # Set the tensor model-parallel, pipeline model-parallel, and
     # data-parallel communicators.
@@ -203,11 +203,14 @@ def _init_autoresume():
         torch.distributed.barrier()
 
 
-def _set_random_seed(seed_):
+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)

megatron/model/distributed.py

@@ -185,6 +185,13 @@ class DistributedDataParallel(DistributedDataParallelBase):
             buffer_.zero()
 
 
+    def broadcast_params(self):
+        for param in self.module.parameters():
+            torch.distributed.broadcast(param.data,
+                                        src=mpu.get_data_parallel_src_rank(),
+                                        group=mpu.get_data_parallel_group())
+
+
     def allreduce_gradients(self):
         """Reduce gradients across data parallel ranks."""
         # If we have buffers, simply reduce the data in the buffer.

megatron/model/fused_layer_norm.py

@@ -23,6 +23,12 @@ from torch.nn.parameter import Parameter
 from torch.nn import init
 import importlib
 
+try:
+    from apex.contrib.layer_norm.layer_norm import FastLayerNormFN
+    HAVE_PERSIST_LAYER_NORM = True
+except:
+    HAVE_PERSIST_LAYER_NORM = False
+
 global fused_mix_prec_layer_norm_cuda
 fused_mix_prec_layer_norm_cuda = None
 
@@ -61,13 +67,23 @@ class FusedLayerNormAffineFunction(torch.autograd.Function):
 
 class MixedFusedLayerNorm(torch.nn.Module):
 
-  def __init__(self, normalized_shape, eps=1e-5):
+  def __init__(self, normalized_shape, eps=1e-5, no_persist_layer_norm=True):
         super(MixedFusedLayerNorm, self).__init__()
 
         global fused_mix_prec_layer_norm_cuda
         fused_mix_prec_layer_norm_cuda = importlib.import_module(
           "fused_mix_prec_layer_norm_cuda")
 
+        # List of hiddens sizes supported in the persistent layer norm kernel
+        # If the hidden size is not supported, fall back to the non-persistent
+        # kernel.
+        persist_ln_hidden_sizes = [1024, 1536, 2048, 2304, 3072, 3840, 4096,
+            5120, 6144, 8192, 10240, 12288, 12800, 15360, 16384, 18432, 20480,
+            24576, 25600, 30720, 32768, 40960, 49152, 65536]
+        if normalized_shape not in persist_ln_hidden_sizes or \
+                not HAVE_PERSIST_LAYER_NORM:
+            no_persist_layer_norm = True
+
         if isinstance(normalized_shape, numbers.Integral):
             normalized_shape = (normalized_shape,)
         self.normalized_shape = torch.Size(normalized_shape)
@@ -75,6 +91,7 @@ class MixedFusedLayerNorm(torch.nn.Module):
         self.weight = Parameter(torch.Tensor(*normalized_shape))
         self.bias = Parameter(torch.Tensor(*normalized_shape))
         self.reset_parameters()
+        self.no_persist_layer_norm = no_persist_layer_norm
 
 
   def reset_parameters(self):
@@ -85,6 +102,10 @@ class MixedFusedLayerNorm(torch.nn.Module):
 
   def forward(self, input):
 
-    return FusedLayerNormAffineFunction.apply(
-      input, self.weight, self.bias, self.normalized_shape,self.eps)
+    if self.no_persist_layer_norm:
+        return FusedLayerNormAffineFunction.apply(
+          input, self.weight, self.bias, self.normalized_shape, self.eps)
+    else:
+        return FastLayerNormFN.apply(
+          input, self.weight, self.bias, self.eps)
 

megatron/model/fused_softmax.py

@@ -81,6 +81,37 @@ class ScaledMaskedSoftmax(torch.autograd.Function):
         return input_grads, None, None
 
 
+class ScaledSoftmax(torch.autograd.Function):
+    """
+    Fused operation which performs following two operations in sequence
+    1. Scale the tensor.
+    2. Perform softmax.
+    """
+
+    @staticmethod
+    def forward(ctx, inputs, scale):
+        import scaled_softmax_cuda
+
+        scale_t = torch.tensor([scale])
+
+        softmax_results = scaled_softmax_cuda.forward(
+            inputs, scale_t[0]
+        )
+        ctx.save_for_backward(softmax_results, scale_t)
+        return softmax_results
+
+    @staticmethod
+    def backward(ctx, output_grads):
+        import scaled_softmax_cuda
+
+        softmax_results, scale_t = ctx.saved_tensors
+
+        input_grads = scaled_softmax_cuda.backward(
+            output_grads, softmax_results, scale_t[0]
+        )
+        return input_grads, None, None
+
+
 class FusedScaleMaskSoftmax(nn.Module):
     """
     fused operation: scaling + mask + softmax
@@ -137,12 +168,11 @@ class FusedScaleMaskSoftmax(nn.Module):
         if (
             self.scaled_masked_softmax_fusion  # user want to fuse
             and self.input_in_float16  # input must be fp16
-            and mask is not None  # mask tensor must not be None
-            and 16 < sk <= 2048  # sk must be 16 ~ 2048
+            and 16 < sk <= 4096  # sk must be 16 ~ 2048
             and sq % 4 == 0  # sq must be divisor of 4
             and attn_batches % 4 == 0  # np * b must be divisor of 4
         ):
-            if 0 <= sk <= 2048:
+            if 0 <= sk <= 4096:
                 batch_per_block = self.get_batch_per_block(sq, sk, b, np)
 
                 if self.attn_mask_type == AttnMaskType.causal:
@@ -166,7 +196,10 @@ class FusedScaleMaskSoftmax(nn.Module):
             return probs.view(b, np, sq, sk)
         else:
             # input is 4D tensor (b, np, sq, sk)
-            return ScaledMaskedSoftmax.apply(input, mask, scale)
+            if mask is not None:
+                return ScaledMaskedSoftmax.apply(input, mask, scale)
+            else:
+                return ScaledSoftmax.apply(input, scale)
 
     def forward_torch_softmax(self, input, mask):
         if self.input_in_float16 and self.softmax_in_fp32:

megatron/model/language_model.py

@@ -336,10 +336,6 @@ class TransformerLanguageModel(MegatronModule):
         # Decoder (usually set to False, True if part of an encoder-decoder
         # architecture and in decoder-only stage).
         if self.add_decoder:
-            # Temporary assertion until we verify correctness of pipeline parallelism
-            # implementation of T5.
-            assert args.pipeline_model_parallel_size == 1, \
-                'pipeline parallelism is not supported in the presence of decoder'
             self.decoder = ParallelTransformer(
                 self.init_method,
                 output_layer_init_method,

megatron/model/module.py

@@ -51,8 +51,7 @@ class MegatronModule(torch.nn.Module):
 
 
     def word_embeddings_weight(self):
-        if not mpu.is_pipeline_last_stage(ignore_virtual=True) or \
-                mpu.get_pipeline_model_parallel_world_size() == 1:
+        if self.pre_process:
             return self.language_model.embedding.word_embeddings.weight
         else:
             if not self.share_word_embeddings:
@@ -73,6 +72,16 @@ class MegatronModule(torch.nn.Module):
         if args.pipeline_model_parallel_size == 1:
             return
 
+        if not torch.distributed.is_initialized():
+            if not getattr(MegatronModule, "embedding_warning_printed", False):
+                print("WARNING! Distributed processes aren't initialized, so "
+                      "word embeddings in the last layer are not initialized. "
+                      "If you are just manipulating a model this is fine, but "
+                      "this needs to be handled manually. If you are training "
+                      "something is definitely wrong.")
+                MegatronModule.embedding_warning_printed = True
+            return
+
         # Parameters are shared between the word embeddings layers, and the
         # heads at the end of the model. In a pipelined setup with more than
         # one stage, the initial embedding layer and the head are on different
@@ -85,7 +94,8 @@ class MegatronModule(torch.nn.Module):
         # 3. In the training loop, before an all-reduce between the grads of
         #    the two word_embeddings layers to ensure that every applied weight
         #    update is the same on both stages.
-        if mpu.is_pipeline_last_stage():
+        if mpu.is_pipeline_last_stage() and \
+                not self.pre_process:
             assert not mpu.is_pipeline_first_stage()
             self._word_embeddings_for_head_key = 'word_embeddings_for_head'
             # set word_embeddings weights to 0 here, then copy first
@@ -96,21 +106,10 @@ class MegatronModule(torch.nn.Module):
             self.word_embeddings.weight.data.fill_(0)
             self.word_embeddings.weight.shared = True
 
-        if not torch.distributed.is_initialized():
-            if not getattr(MegatronModule, "embedding_warning_printed", False):
-                print("WARNING! Distributed processes aren't initialized, so "
-                      "word embeddings in the last layer are not initialized. "
-                      "If you are just manipulating a model this is fine, but "
-                      "this needs to be handled manually. If you are training "
-                      "something is definitely wrong.")
-                MegatronModule.embedding_warning_printed = True
-            return
-
         # Zero out initial weights for decoder embedding.
         # NOTE: We don't currently support T5 with the interleaved schedule.
         if not mpu.is_pipeline_first_stage(ignore_virtual=True) and \
-                not mpu.is_pipeline_last_stage(ignore_virtual=True) and \
-                mpu.is_rank_in_embedding_group():
+                self.pre_process:
             self.language_model.embedding.zero_parameters()
 
         # Ensure that first and last stages have the same initial parameter
@@ -118,21 +117,17 @@ class MegatronModule(torch.nn.Module):
         if mpu.is_rank_in_embedding_group():
             torch.distributed.all_reduce(self.word_embeddings_weight().data,
                                          group=mpu.get_embedding_group())
-            # All-reduce other embeddings as well as necessary. The last stage
-            # does not have these other embeddings, so just create placeholder
-            # tensors of the right shape with all zeros.
-            # NOTE: We don't currently support T5 with the interleaved schedule.
-            if args.pipeline_model_parallel_split_rank is not None:
-                # TODO: Support tokentype embedding.
-                dimensions = (args.max_position_embeddings, args.hidden_size)
-                if mpu.is_pipeline_last_stage(ignore_virtual=True):
-                    position_embeddings = torch.nn.Embedding(*dimensions).cuda()
-                    position_embeddings.weight.data.fill_(0)
-                else:
-                    self.language_model.embedding.cuda()
-                    position_embeddings = self.language_model.embedding.position_embeddings
-                torch.distributed.all_reduce(position_embeddings.weight.data,
-                                             group=mpu.get_embedding_group())
+
+        # Ensure that encoder(first stage) and decoder(split stage) position
+        # embeddings have the same initial parameter values
+        # NOTE: We don't currently support T5 with the interleaved schedule.
+        if mpu.is_rank_in_position_embedding_group() and \
+                args.pipeline_model_parallel_split_rank is not None:
+            # TODO: Support tokentype embedding.
+            self.language_model.embedding.cuda()
+            position_embeddings = self.language_model.embedding.position_embeddings
+            torch.distributed.all_reduce(position_embeddings.weight.data,
+                                         group=mpu.get_position_embedding_group())
 
 
 def conversion_helper(val, conversion):

megatron/model/transformer.py

@@ -27,7 +27,6 @@ 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
 
-
 """ We use the following notation throughout this file:
      h: hidden size
      n: number of attention heads
@@ -43,6 +42,29 @@ from megatron.model.utils import attention_mask_func, openai_gelu, erf_gelu
         hyperparameters: transformer hyperparameters
 """
 
+
+class DropPath(MegatronModule):
+    """Drop paths (Stochastic Depth) per sample 
+    (when applied in main path of residual blocks).
+    """
+
+    def __init__(self, drop_prob=0.):
+        super(DropPath, self).__init__()
+        self.drop_prob = drop_prob
+
+    def forward(self, hidden_state):
+        if self.drop_prob == 0. or not self.training:
+            return hidden_state
+        keep_prob = 1 - self.drop_prob
+        # work with diff dim tensors, not just 2D ConvNets
+        shape = (hidden_state.shape[0],) + (1,) * (hidden_state.ndim - 1)
+        random_tensor = keep_prob + \
+            torch.rand(shape, dtype=hidden_state.dtype, device=hidden_state.device)
+        random_tensor.floor_()  # binarize
+        output = hidden_state.div(keep_prob) * random_tensor
+        return output
+
+
 class ParallelMLP(MegatronModule):
     """MLP.
 
@@ -407,7 +429,8 @@ class ParallelTransformerLayer(MegatronModule):
 
     def __init__(self, init_method, output_layer_init_method,
                  layer_number, layer_type=LayerType.encoder,
-                 self_attn_mask_type=AttnMaskType.padding):
+                 self_attn_mask_type=AttnMaskType.padding,
+                 drop_path_rate=0.):
         args = get_args()
 
         super(ParallelTransformerLayer, self).__init__()
@@ -423,7 +446,8 @@ class ParallelTransformerLayer(MegatronModule):
         # Layernorm on the input data.
         self.input_layernorm = LayerNorm(
             args.hidden_size,
-            eps=args.layernorm_epsilon)
+            eps=args.layernorm_epsilon,
+            no_persist_layer_norm=args.no_persist_layer_norm)
 
         # Self attention.
         self.self_attention = ParallelAttention(
@@ -434,11 +458,13 @@ class ParallelTransformerLayer(MegatronModule):
             attn_mask_type=self_attn_mask_type)
         self.hidden_dropout = args.hidden_dropout
         self.bias_dropout_fusion = args.bias_dropout_fusion
+        self.drop_path = DropPath(drop_path_rate) if drop_path_rate > 0.0 else None
 
         # Layernorm on the attention output
         self.post_attention_layernorm = LayerNorm(
             args.hidden_size,
-            eps=args.layernorm_epsilon)
+            eps=args.layernorm_epsilon,
+            no_persist_layer_norm=args.no_persist_layer_norm)
 
         if self.layer_type == LayerType.decoder:
             self.inter_attention = ParallelAttention(
@@ -449,7 +475,8 @@ class ParallelTransformerLayer(MegatronModule):
             # Layernorm on the attention output.
             self.post_inter_attention_layernorm = LayerNorm(
                 args.hidden_size,
-                eps=args.layernorm_epsilon)
+                eps=args.layernorm_epsilon,
+                no_persist_layer_norm=args.no_persist_layer_norm)
 
         # MLP
         self.mlp = ParallelMLP(init_method,
@@ -475,25 +502,31 @@ class ParallelTransformerLayer(MegatronModule):
         else:
             residual = hidden_states
 
-        # jit scripting for a nn.module (with dropout) is not
-        # trigerring the fusion kernel. For now, we use two
-        # different nn.functional routines to account for varying
-        # dropout semantics during training and inference phases.
-        if self.bias_dropout_fusion:
-            if self.training:
-                bias_dropout_add_func = bias_dropout_add_fused_train
+        if self.drop_path is None:
+            # jit scripting for a nn.module (with dropout) is not
+            # trigerring the fusion kernel. For now, we use two
+            # different nn.functional routines to account for varying
+            # dropout semantics during training and inference phases.
+            if self.bias_dropout_fusion:
+                if self.training:
+                    bias_dropout_add_func = bias_dropout_add_fused_train
+                else:
+                    bias_dropout_add_func = bias_dropout_add_fused_inference
             else:
-                bias_dropout_add_func = bias_dropout_add_fused_inference
-        else:
-            bias_dropout_add_func = get_bias_dropout_add(self.training)
+                bias_dropout_add_func = get_bias_dropout_add(self.training)
 
-        # re-enable torch grad to enable fused optimization.
-        with torch.enable_grad():
-            layernorm_input = bias_dropout_add_func(
-                attention_output,
-                attention_bias.expand_as(residual),
-                residual,
-                self.hidden_dropout)
+            # re-enable torch grad to enable fused optimization.
+            with torch.enable_grad():
+                layernorm_input = bias_dropout_add_func(
+                    attention_output,
+                    attention_bias.expand_as(residual),
+                    residual,
+                    self.hidden_dropout)
+        else:
+            out = torch.nn.functional.dropout(attention_output + attention_bias,
+                                              p=self.hidden_dropout,
+                                              training=self.training)
+            layernorm_input = residual + self.drop_path(out)
 
         # Layer norm post the self attention.
         layernorm_output = self.post_attention_layernorm(layernorm_input)
@@ -529,24 +562,57 @@ class ParallelTransformerLayer(MegatronModule):
         else:
             residual = layernorm_input
 
-        # re-enable torch grad to enable fused optimization.
-        with torch.enable_grad():
-            output = bias_dropout_add_func(
-                mlp_output,
-                mlp_bias.expand_as(residual),
-                residual,
-                self.hidden_dropout)
+        if self.drop_path is None:
+            # re-enable torch grad to enable fused optimization.
+            with torch.enable_grad():
+                output = bias_dropout_add_func(
+                    mlp_output,
+                    mlp_bias.expand_as(residual),
+                    residual,
+                    self.hidden_dropout)
+        else:
+            out = torch.nn.functional.dropout(mlp_output + mlp_bias,
+                                              p=self.hidden_dropout,
+                                              training=self.training)
+            output = residual + self.drop_path(out)
 
         return output
 
 
+class NoopTransformerLayer(MegatronModule):
+    """A single 'no-op' transformer layer.
+
+    The sole purpose of this layer is for when a standalone embedding layer
+    is used (i.e., args.standalone_embedding_stage == True). In this case,
+    zero transformer layers are assigned when pipeline rank == 0. Additionally,
+    when virtual pipeline rank >= 1, zero total model parameters are created
+    (virtual rank 0 contains the input embedding). This results in the model's
+    input and output tensors being the same, which causes an error when
+    performing certain memory optimiations on the output tensor (e.g.,
+    deallocating it). Thus, this layer disconnects the input from the output
+    via a clone. Since ranks containing a no-op layer are generally under-
+    utilized (both compute and memory), there's no worry of any performance
+    degredation.
+    """
+
+    def __init__(self, layer_number):
+        super().__init__()
+        self.layer_number = layer_number
+
+    def forward(self, hidden_states, attention_mask,
+                encoder_output=None, enc_dec_attn_mask=None,
+                inference_params=None):
+        return hidden_states.clone()
+
+
 class ParallelTransformer(MegatronModule):
     """Transformer class."""
 
     def __init__(self, init_method, output_layer_init_method,
                  layer_type=LayerType.encoder,
                  self_attn_mask_type=AttnMaskType.padding,
-                 pre_process=True, post_process=True):
+                 pre_process=True, post_process=True,
+                 drop_path_rate=0.0):
         super(ParallelTransformer, self).__init__()
         args = get_args()
 
@@ -555,6 +621,7 @@ class ParallelTransformer(MegatronModule):
         self.pre_process = pre_process
         self.post_process = post_process
         self.input_tensor = None
+        self.drop_path_rate = drop_path_rate
 
         # Store activation checkpoiting flag.
         self.activations_checkpoint_method = args.activations_checkpoint_method
@@ -565,6 +632,8 @@ class ParallelTransformer(MegatronModule):
         self.num_layers = mpu.get_num_layers(
             args, args.model_type == ModelType.encoder_and_decoder)
 
+        self.drop_path_rates = [rate.item() for rate in torch.linspace(0, self.drop_path_rate, args.num_layers)]
+
         # Transformer layers.
         def build_layer(layer_number):
             return ParallelTransformerLayer(
@@ -572,11 +641,13 @@ class ParallelTransformer(MegatronModule):
                 output_layer_init_method,
                 layer_number,
                 layer_type=layer_type,
-                self_attn_mask_type=self_attn_mask_type)
+                self_attn_mask_type=self_attn_mask_type,
+                drop_path_rate=self.drop_path_rates[layer_number - 1])
         if args.virtual_pipeline_model_parallel_size is not None:
             assert args.num_layers % args.virtual_pipeline_model_parallel_size == 0, \
                 'num_layers_per_stage must be divisible by ' \
                 'virtual_pipeline_model_parallel_size'
+            assert args.model_type != ModelType.encoder_and_decoder
             # Number of layers in each model chunk is the number of layers in the stage,
             # divided by the number of model chunks in a stage.
             self.num_layers = self.num_layers // args.virtual_pipeline_model_parallel_size
@@ -593,16 +664,38 @@ class ParallelTransformer(MegatronModule):
                 (mpu.get_pipeline_model_parallel_rank() * self.num_layers)
         else:
             # Each stage gets a contiguous set of layers.
-            offset = mpu.get_pipeline_model_parallel_rank() * self.num_layers
-
-        self.layers = torch.nn.ModuleList(
-            [build_layer(i + 1 + offset) for i in range(self.num_layers)])
+            if args.model_type == ModelType.encoder_and_decoder and \
+                    mpu.get_pipeline_model_parallel_world_size() > 1:
+                pipeline_rank = mpu.get_pipeline_model_parallel_rank()
+                if layer_type == LayerType.encoder:
+                    offset = pipeline_rank * self.num_layers
+                else:
+                    num_ranks_in_enc = args.pipeline_model_parallel_split_rank
+                    offset = (pipeline_rank - num_ranks_in_enc) * self.num_layers
+            else:
+                offset = mpu.get_pipeline_model_parallel_rank() * self.num_layers
+
+        if self.num_layers == 0:
+            # When a standalone embedding stage is used (e.g.,
+            # args.standalone_embedding_stage == True), virtual pipeline ranks
+            # on pipeline rank 0 will have zero transformer layers assigned to
+            # them. This results in the model's input and output tensors to be
+            # the same, which will cause failure for certain output tensor
+            # optimizations (e.g., pipeline output deallocation). To remedy
+            # this, we assign a 'no-op' layer on these ranks, which will
+            # disconnect the input tensor from the output tensor.
+            self.num_layers = 1
+            self.layers = torch.nn.ModuleList([ NoopTransformerLayer(1) ])
+        else:
+            self.layers = torch.nn.ModuleList(
+                [build_layer(i + 1 + offset) for i in range(self.num_layers)])
 
         if self.post_process:
             # Final layer norm before output.
             self.final_layernorm = LayerNorm(
                 args.hidden_size,
-                eps=args.layernorm_epsilon)
+                eps=args.layernorm_epsilon,
+                no_persist_layer_norm=args.no_persist_layer_norm)
 
     def _get_layer(self, layer_number):
         return self.layers[layer_number]
@@ -622,23 +715,6 @@ class ParallelTransformer(MegatronModule):
                 return x_
             return custom_forward
 
-        def distribute_checkpointed_activations_helper(layer_number):
-            """Distribute checkpointed activations across the tensor model
-               Parallel ranks if the `distribute-checkpointed-activations
-               is on and either of the following conditions is met:
-                 - it is not the first layer in the in the pipeline stage.
-                   The first layer is used in the pipeline parallelism 
-                   and changing its shape throws error in the backward pass.
-                 - we are at the first pipline stage so the input tensor is
-                   not used in pipeline parallelism. Note that no pipeline
-                   parallelism is a special case of this.
-            """
-            not_first_layer_in_pipeline_stage = (layer_number > 0)
-            is_first_pipeline_stage = (
-                mpu.get_pipeline_model_parallel_rank() == 0)
-            return self.distribute_checkpointed_activations and \
-                (not_first_layer_in_pipeline_stage or is_first_pipeline_stage)
-
         if self.activations_checkpoint_method == 'uniform':
             # Uniformly divide the total number of Transformer layers and checkpoint
             # the input activation of each divided chunk.
@@ -647,7 +723,7 @@ class ParallelTransformer(MegatronModule):
             while l < self.num_layers:
                 hidden_states = mpu.checkpoint(
                     custom(l, l + self.activations_checkpoint_num_layers),
-                    distribute_checkpointed_activations_helper(l),
+                    self.distribute_checkpointed_activations,
                     hidden_states, attention_mask, encoder_output, enc_dec_attn_mask)
                 l += self.activations_checkpoint_num_layers
         elif self.activations_checkpoint_method == 'block':
@@ -658,7 +734,7 @@ class ParallelTransformer(MegatronModule):
                 if l < self.activations_checkpoint_num_layers:
                     hidden_states = mpu.checkpoint(
                         custom(l, l + 1),
-                        distribute_checkpointed_activations_helper(l),
+                        self.distribute_checkpointed_activations,
                         hidden_states, attention_mask, encoder_output, enc_dec_attn_mask)
                 else:
                     hidden_states = custom(l, l + 1)(
@@ -699,9 +775,32 @@ class ParallelTransformer(MegatronModule):
             # See set_input_tensor()
             hidden_states = self.input_tensor
 
+        # Viewless tensor.
+        # - We only need to create a viewless tensor in the case of micro batch
+        #   size (mbs) == 1, since in this case, 'hidden_states.transpose()'
+        #   above creates a view tensor, and '.contiguous()' is a pass-through.
+        #   For mbs >= 2, '.contiguous()' creates a new tensor, eliminating
+        #   the need to make it viewless.
+        #
+        #   However, we don't explicitly check mbs == 1 here because
+        #   make_viewless_tensor() has negligible overhead when its input
+        #   is already viewless.
+        # 
+        # - For the 'else' case above, calling make_viewless_tensor() here is
+        #   likely redundant, since p2p_communication.py (likely originator)
+        #   already creates viewless tensors. That said, make_viewless_tensor()
+        #   is called here to be future-proof and corner-case-proof.
+        hidden_states = mpu.make_viewless_tensor(
+            hidden_states,
+            requires_grad = True,
+            keep_graph = True,
+        )
+
+        # Transpose encoder output.
         if encoder_output is not None:
-             encoder_output = encoder_output.transpose(0, 1).contiguous()
+            encoder_output = encoder_output.transpose(0, 1).contiguous()
 
+        # Forward pass.
         if self.activations_checkpoint_method is not None:
             hidden_states = self._checkpointed_forward(hidden_states,
                                                        attention_mask,
@@ -725,5 +824,5 @@ class ParallelTransformer(MegatronModule):
             output = self.final_layernorm(hidden_states)
         else:
             output = hidden_states
-        
+
         return output

megatron/model/vision/classification.py

+# coding=utf-8
+# Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Vision Transformer(VIT) model."""
+
+import torch
+from torch.nn.init import trunc_normal_
+from megatron import get_args
+from megatron.model.utils import get_linear_layer
+from megatron.model.vision.vit_backbone import VitBackbone, VitMlpHead
+from megatron.model.vision.mit_backbone import mit_b3_avg
+from megatron.model.module import MegatronModule
+
+class VitClassificationModel(MegatronModule):
+    """Vision Transformer Model."""
+
+    def __init__(self, num_classes, finetune=False,
+                 pre_process=True, post_process=True):
+        super(VitClassificationModel, self).__init__()
+        args = get_args()
+
+        self.hidden_size = args.hidden_size
+        self.num_classes = num_classes
+        self.finetune = finetune
+        self.pre_process = pre_process
+        self.post_process = post_process
+        self.backbone = VitBackbone(
+            pre_process=self.pre_process,
+            post_process=self.post_process,
+            single_token_output=True
+        )
+        
+        if self.post_process:
+            if not self.finetune:
+                self.head = VitMlpHead(self.hidden_size, self.num_classes)
+            else:
+                self.head = get_linear_layer(
+                    self.hidden_size,
+                    self.num_classes,
+                    torch.nn.init.zeros_
+                )
+
+    def set_input_tensor(self, input_tensor):
+        """See megatron.model.transformer.set_input_tensor()"""
+        self.backbone.set_input_tensor(input_tensor)
+
+    def forward(self, input):
+        hidden_states = self.backbone(input)
+
+        if self.post_process:
+            hidden_states = self.head(hidden_states)
+
+        return hidden_states
+
+
+class MitClassificationModel(MegatronModule):
+    """Mix vision Transformer Model."""
+
+    def __init__(self, num_classes,
+                 pre_process=True, post_process=True):
+        super(MitClassificationModel, self).__init__()
+        args = get_args()
+
+        self.hidden_size = args.hidden_size
+        self.num_classes = num_classes
+
+        self.backbone = mit_b3_avg()
+        self.head = torch.nn.Linear(512, num_classes)
+        self.apply(self._init_weights)
+
+    def _init_weights(self, m):
+        if isinstance(m, torch.nn.Linear):
+            trunc_normal_(m.weight, std=.02)
+            if isinstance(m, torch.nn.Linear) and m.bias is not None:
+                torch.nn.init.constant_(m.bias, 0)
+
+    def set_input_tensor(self, input_tensor):
+        """See megatron.model.transformer.set_input_tensor()"""
+        pass
+
+    def forward(self, input):
+        hidden_states = self.backbone(input)
+        hidden_states = self.head(hidden_states)
+
+        return hidden_states

megatron/model/vision/dino.py

+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the Apache license found in the
+# LICENSE file in the root directory of this source tree.
+
+# copied from https://github.com/facebookresearch/dino/blob/main/main_dino.py
+# reworked/refactored some parts to make it run in Megatron.
+import math
+import apex
+import einops
+import torch
+import numpy as np
+import torch.nn.functional as F
+from torch.nn.init import trunc_normal_
+from megatron import get_args, print_rank_0
+from megatron.model.utils import get_linear_layer
+from megatron.model.vision.vit_backbone import VitBackbone
+from megatron.model.module import MegatronModule
+from megatron.model.vision.mit_backbone import mit_b5_avg
+from megatron.model.vision.esvit_swin_backbone import get_swin
+
+
+class DINOLoss(torch.nn.Module):
+    def __init__(self, out_dim, ncrops, warmup_teacher_temp, teacher_temp,
+                 warmup_teacher_temp_epochs, nepochs, student_temp=0.1,
+                 center_momentum=0.9):
+        super().__init__()
+        self.student_temp = student_temp
+        self.center_momentum = center_momentum
+        self.ncrops = ncrops
+        self.register_buffer("center", torch.zeros(1, out_dim))
+        # we apply a warm up for the teacher temperature because
+        # a too high temperature makes the training instable at the beginning
+        self.teacher_temp_schedule = np.concatenate((
+            np.linspace(warmup_teacher_temp,
+                        teacher_temp, warmup_teacher_temp_epochs),
+            np.ones(nepochs - warmup_teacher_temp_epochs) * teacher_temp
+        ))
+        self.teacher_temp = teacher_temp
+
+    def forward(self, student_output, teacher_output, iteration):
+        """
+        Cross-entropy between softmax outputs of the teacher
+        and student network.
+        """
+        args = get_args()
+        student_out = student_output / self.student_temp
+        student_out = student_out.chunk(self.ncrops)
+
+        epoch = iteration // args.iter_per_epoch
+
+        # teacher centering and sharpening
+        temp = self.teacher_temp_schedule[epoch]
+        teacher_out = F.softmax((teacher_output - self.center) / temp, dim=-1)
+
+        teacher_out = teacher_out.detach().chunk(2)
+
+        total_loss = 0
+        n_loss_terms = 0
+        for iq, q in enumerate(teacher_out):
+            for v in range(len(student_out)):
+                if v == iq:
+                    # we skip cases where student and teacher operate on the same view
+                    continue
+                loss = torch.sum(-q * F.log_softmax(student_out[v], dim=-1), dim=-1)
+                total_loss += loss.mean()
+                n_loss_terms += 1
+        total_loss /= n_loss_terms
+        self.update_center(teacher_output)
+        return total_loss
+
+    @torch.no_grad()
+    def update_center(self, teacher_output):
+        """
+        Update center used for teacher output.
+        """
+        batch_center = torch.sum(teacher_output, dim=0, keepdim=True)
+        torch.distributed.all_reduce(batch_center)
+        batch_center = batch_center / (len(teacher_output) * torch.distributed.get_world_size())
+        self.center = self.center * self.center_momentum + batch_center * (1 - self.center_momentum)
+
+class DINOHead(torch.nn.Module):
+    def __init__(self, in_dim, out_dim, norm_last_layer=True, nlayers=3):
+        super().__init__()
+        args = get_args()
+        hidden_dim = args.dino_head_hidden_size
+        bottleneck_dim = args.dino_bottleneck_size
+        nlayers = max(nlayers, 1)
+        if nlayers == 1:
+            self.mlp = torch.nn.Linear(in_dim, bottleneck_dim)
+        else:
+            layers = [torch.nn.Linear(in_dim, hidden_dim)]
+            layers.append(torch.nn.GELU())
+            for _ in range(nlayers - 2):
+                layers.append(torch.nn.Linear(hidden_dim, hidden_dim))
+                layers.append(torch.nn.GELU())
+            layers.append(torch.nn.Linear(hidden_dim, bottleneck_dim))
+            self.mlp = torch.nn.Sequential(*layers)
+        self.apply(self._init_weights)
+        self.last_layer = torch.nn.utils.weight_norm(torch.nn.Linear(bottleneck_dim, out_dim, bias=False))
+        self.last_layer.weight_g.data.fill_(1)
+        if norm_last_layer:
+            self.last_layer.weight_g.requires_grad = False
+
+    def _init_weights(self, m):
+        if isinstance(m, torch.nn.Linear):
+            trunc_normal_(m.weight, std=.02)
+            if isinstance(m, torch.nn.Linear) and m.bias is not None:
+                torch.nn.init.constant_(m.bias, 0)
+
+    def forward(self, x):
+        x = self.mlp(x)
+        x = torch.nn.functional.normalize(x, dim=-1, p=2)
+        x = self.last_layer(x)
+        return x
+
+
+class MultiCropWrapper(MegatronModule):
+
+    """
+    Perform forward pass separately on each resolution input.
+    The inputs corresponding to a single resolution are clubbed and single
+    forward is run on the same resolution inputs. Hence we do several
+    forward passes = number of different resolutions used. We then
+    concatenate all the output features and run the head forward on these
+    concatenated features.
+    """
+    def __init__(self, backbone, head):
+        super(MultiCropWrapper, self).__init__()
+        # disable layers dedicated to ImageNet labels classification
+        #backbone.fc, backbone.head = torch.nn.Identity(), torch.nn.Identity()
+        self.backbone = backbone
+        self.head = head
+
+    def forward(self, x):
+        # convert to list
+        if not isinstance(x, list):
+            x = [x]
+        idx_crops = torch.cumsum(torch.unique_consecutive(
+            torch.tensor([inp.shape[-1] for inp in x]),
+            return_counts=True,
+        )[1], 0)
+
+        start_idx = 0
+        for end_idx in idx_crops:
+            _out = self.backbone(torch.cat(x[start_idx: end_idx]))
+            if start_idx == 0:
+                output = _out
+            else:
+                output = torch.cat((output, _out))
+            start_idx = end_idx
+        # Run the head forward on the concatenated features.
+        if self.training:
+            return self.head(output)
+        else:
+            return output
+
+
+def cosine_scheduler(base_value, final_value, epochs, niter_per_ep,
+                     warmup_epochs=0, start_warmup_value=0):
+    warmup_schedule = np.array([])
+    warmup_iters = warmup_epochs * niter_per_ep
+    if warmup_epochs > 0:
+        warmup_schedule = \
+                np.linspace(start_warmup_value, base_value, warmup_iters)
+
+    iters = np.arange(epochs * niter_per_ep - warmup_iters)
+    schedule = final_value + 0.5 * (base_value - final_value) \
+        * (1 + np.cos(np.pi * iters / len(iters)))
+
+    schedule = np.concatenate((warmup_schedule, schedule))
+    assert len(schedule) == epochs * niter_per_ep
+    return schedule
+
+
+def get_student_backbone_and_num_features(pre_process=True, post_process=True):
+    args = get_args()
+
+    if args.vision_backbone_type == 'vit':
+        student = VitBackbone(pre_process=pre_process,
+                              post_process=post_process,
+                              drop_path_rate=0.1,
+                              single_token_output=True)
+        num_features = args.hidden_size
+    elif args.vision_backbone_type == 'mit':
+        student = mit_b5_avg(drop_path_rate=0.1)
+        num_features = 512
+    elif args.vision_backbone_type == 'swin':
+        student = get_swin()
+        num_features = student.num_features
+    else:
+        raise Exception('{} vision backbone is not supported.'.format(
+                              args.vision_backbone_type))
+ 
+    return student, num_features
+
+def get_teacher_backbone_and_num_features(pre_process=True, post_process=True):
+    args = get_args()
+
+    if args.vision_backbone_type == 'vit':
+        teacher = VitBackbone(pre_process=pre_process,
+                              post_process=post_process,
+                              single_token_output=True)
+        num_features = args.hidden_size
+    elif args.vision_backbone_type == 'mit':
+        teacher = mit_b5_avg(drop_path_rate=0.0)
+        num_features = 512
+    elif args.vision_backbone_type == 'swin':
+        teacher = get_swin(is_teacher=True)
+        num_features = teacher.num_features
+    else:
+        raise Exception('{} vision backbone is not supported.'.format(
+                              args.vision_backbone_type))
+    return teacher, num_features
+
+
+class DINOPretrainModel(MegatronModule):
+    def __init__(self, pre_process=True, post_process=True):
+        super(DINOPretrainModel, self).__init__()
+        args = get_args()
+        self.out_dim = 65536
+
+        self.dino_loss = DINOLoss(
+            self.out_dim,
+            args.dino_local_crops_number + 2,
+            args.dino_warmup_teacher_temp,
+            args.dino_teacher_temp,
+            args.dino_warmup_teacher_temp_epochs,
+            300,
+        )
+
+        self.pre_process = pre_process
+        self.post_process = post_process
+        self.momentum_teacher = 0.996
+
+        student_backbone, num_features = \
+            get_student_backbone_and_num_features(pre_process, post_process)
+
+        self.student = MultiCropWrapper(
+            student_backbone,
+            DINOHead(num_features, self.out_dim,
+                     norm_last_layer=args.dino_norm_last_layer)
+        )
+
+        self.momentum_schedule = cosine_scheduler(
+            self.momentum_teacher, 1,
+            args.train_iters // args.iter_per_epoch,
+            args.iter_per_epoch
+        )
+
+        teacher_backbone, num_features = \
+            get_teacher_backbone_and_num_features(pre_process, post_process)
+        self.teacher = MultiCropWrapper(
+            teacher_backbone,
+            DINOHead(num_features, self.out_dim)
+        )
+        self.teacher.load_state_dict(self.student.state_dict())
+
+        for p in self.teacher.parameters():
+            if hasattr(p, "requires_grad") and p.requires_grad is not None:
+                p.requires_grad = False
+
+    def set_input_tensor(self, tensor):
+        pass
+
+    def forward(self, input):
+        student_output = None
+        if self.training:
+            student_output = self.student(input)
+            teacher_output = self.teacher(input[:2])
+        else:
+            teacher_output = self.teacher(input)
+        return student_output, teacher_output
+
+    def cancel_gradients_last_layer(self, iteration):
+        args = get_args()
+        epoch = iteration // args.iter_per_epoch
+        if epoch < args.dino_freeze_last_layer:
+            for n, p in self.student.named_parameters():
+                if "last_layer" in n:
+                    p.grad = None
+
+    def update_momentum(self, iteration):
+        with torch.no_grad():
+            m = self.momentum_schedule[iteration]
+            for param_q, param_k in zip(self.student.parameters(), self.teacher.parameters()):
+                param_k.data.mul_(m).add_((1 - m) * param_q.detach().data)
+

megatron/model/vision/inpainting.py

+# coding=utf-8
+# Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.
+#
+# This source code is licensed under the BSD license found in the
+# LICENSE file in the root directory of this source tree.
+i
+import math
+import apex
+import einops
+import torch
+import torch.nn.functional as F
+from megatron import get_args, print_rank_0
+from megatron.model.utils import get_linear_layer
+from megatron.model.vision.vit_backbone import VitBackbone
+from megatron.model.module import MegatronModule
+from megatron.model.vision.mit_backbone import mit_b3
+from megatron.model.vision.utils import resize_
+
+
+class VitInpaintingModel(MegatronModule):
+
+    def __init__(self, pre_process=True, post_process=True):
+        super(VitInpaintingModel, self).__init__()
+        args = get_args()
+
+        self.pre_process = pre_process
+        self.post_process = post_process
+        self.hidden_size = args.hidden_size
+        self.backbone = VitBackbone(
+            pre_process=self.pre_process,
+            post_process=self.post_process,
+            class_token=False,
+        )
+        self.patch_dim = args.patch_dim
+        self.img_h = args.img_h
+        self.img_w = args.img_w
+        self.seq_length = args.seq_length
+        # full mask
+
+        if self.post_process:
+            self.linear_decoder = get_linear_layer(
+                self.hidden_size,
+                self.backbone.flatten_dim,
+                torch.nn.init.zeros_
+            )
+
+    def set_input_tensor(self, input_tensor):
+        self.backbone.set_input_tensor(input_tensor)
+
+    def forward(self, input):
+
+        hidden_states = self.backbone(input)
+
+        if not self.post_process:
+            return hidden_states
+        decoded_output = self.linear_decoder(hidden_states)
+        output = einops.rearrange(
+                decoded_output,
+                "b (h w) (p1 p2 c) -> b c (h p1) (w p2)",
+                p1=self.patch_dim,
+                p2=self.patch_dim,
+                h=self.img_h//self.patch_dim,
+                w=self.img_w//self.patch_dim,
+            )
+
+        return output
+
+
+class MLP(torch.nn.Module):
+    """
+    Linear Embedding
+    """
+    def __init__(self, input_dim=2048, embed_dim=768):
+        super().__init__()
+        self.proj = torch.nn.Linear(input_dim, embed_dim)
+
+    def forward(self, x):
+        x = x.flatten(2).transpose(1, 2)
+        x = self.proj(x)
+        return x
+
+
+class MitInpaintingModel(MegatronModule):
+    """Mix vision Transformer Model."""
+
+    def __init__(self, pre_process=True, post_process=True):
+        super(MitInpaintingModel, self).__init__()
+        self.pre_process = pre_process
+        self.post_process = post_process
+
+        args = get_args()
+        self.patch_dim = args.patch_dim
+        self.img_h = args.img_h
+        self.img_w = args.img_w
+        self.flatten_dim = self.patch_dim * self.patch_dim * 3
+        self.backbone = mit_b3()
+
+        self.in_channels = [64, 128, 320, 512]
+        self.embedding_dim = 768
+
+        c1_in_channels, c2_in_channels, c3_in_channels, c4_in_channels = self.in_channels
+
+        self.linear_c4 = MLP(input_dim=c4_in_channels, embed_dim=self.embedding_dim)
+        self.linear_c3 = MLP(input_dim=c3_in_channels, embed_dim=self.embedding_dim)
+        self.linear_c2 = MLP(input_dim=c2_in_channels, embed_dim=self.embedding_dim)
+        self.linear_c1 = MLP(input_dim=c1_in_channels, embed_dim=self.embedding_dim)
+
+        self.conv_fuse = torch.nn.Conv2d(self.embedding_dim*4, self.embedding_dim, 1, 1, bias=False)
+        self.norm = apex.parallel.SyncBatchNorm(self.embedding_dim)
+        self.dropout = torch.nn.Dropout2d(0.1)
+        
+        self.linear_pred = torch.nn.Conv2d(self.embedding_dim, self.flatten_dim, kernel_size=1)
+    
+    def set_input_tensor(self, input_tensor):
+        """See megatron.model.transformer.set_input_tensor()"""
+        pass
+
+    def forward(self, input):
+        c1, c2, c3, c4 = self.backbone(input)
+
+        n, _, h, w = c4.shape
+        _c4 = self.linear_c4(c4).permute(0, 2, 1).reshape(n, -1, c4.shape[2], c4.shape[3])
+        _c4 = resize(_c4, size=c1.size()[2:], mode='bilinear', align_corners=False)
+    
+        _c3 = self.linear_c3(c3).permute(0, 2, 1).reshape(n, -1, c3.shape[2], c3.shape[3])
+        _c3 = resize(_c3, size=c1.size()[2:], mode='bilinear', align_corners=False)
+
+        _c2 = self.linear_c2(c2).permute(0, 2, 1).reshape(n, -1, c2.shape[2], c2.shape[3])
+        _c2 = resize(_c2, size=c1.size()[2:], mode='bilinear', align_corners=False)
+
+        _c1 = self.linear_c1(c1).permute(0, 2, 1).reshape(n, -1, c1.shape[2], c1.shape[3])
+
+        _c = torch.cat([_c4, _c3, _c2, _c1], dim=1)
+        _c = self.conv_fuse(_c)
+ 
+        x = self.norm(_c)
+        x = F.relu(x, inplace=True)
+        x = self.dropout(x)
+
+        x = self.linear_pred(x)
+
+        output = einops.rearrange(
+            x,
+            "b (c p1 p2) h w -> b c (h p1) (w p2)",
+            p1=self.patch_dim,
+            p2=self.patch_dim,
+            h=self.img_h//self.patch_dim,
+            w=self.img_w//self.patch_dim,
+        )
+
+        return output

megatron/model/vision/knn_monitor.py

+import torch.nn.functional as F
+import torch
+from megatron import print_rank_0, get_args, mpu
+from megatron.data.vit_dataset import ClassificationTransform
+from megatron.data.image_folder import ImageFolder
+
+_FEATURE_BANK = None
+
+
+def build_data_loader(dataset, drop_last=True, shuffle=False):
+    """Data loader. Note that batch-size is the local (per GPU) batch-size."""
+    # Sampler.
+    args = get_args()
+    micro_batch_size = 16
+    num_workers = args.num_workers
+    world_size = mpu.get_data_parallel_world_size()
+    rank = mpu.get_data_parallel_rank()
+    sampler = torch.utils.data.distributed.DistributedSampler(
+        dataset, num_replicas=world_size, rank=rank,
+        drop_last=drop_last, shuffle=shuffle
+    )
+
+    # Data loader. Note that batch size is the per GPU batch size.
+    data_loader = torch.utils.data.DataLoader(
+        dataset,
+        batch_size=micro_batch_size,
+        sampler=sampler,
+        shuffle=False,
+        num_workers=num_workers,
+        drop_last=not drop_last,
+        pin_memory=True,
+    )
+    return data_loader
+
+
+def compute_feature_bank(model):
+    args = get_args()
+    global _FEATURE_BANK
+    feature_bank = []
+    feature_label = []
+
+    train_ds = ImageFolder(
+        root=args.data_path[0],
+        transform=ClassificationTransform((args.img_h, args.img_w), train=False),
+        data_per_class_fraction=1.0
+    )
+    classes = len(train_ds.classes)
+    dataloader = build_data_loader(train_ds)
+     
+    for m in model:
+        m.eval()
+
+    with torch.no_grad():
+        for i, batch in enumerate(dataloader):
+            images = batch[0].cuda().contiguous()
+            labels = batch[1].cuda().contiguous()
+            student_feature, teacher_feature = model[0](images)
+            feature = F.normalize(teacher_feature.float(), dim=1)
+            feature_bank.append(feature)
+            feature_label.append(labels)
+    
+    for m in model:
+        m.train()
+
+    # [N', D]
+    feature_bank = torch.cat(feature_bank, dim=0).contiguous()
+    feature_label = torch.cat(feature_label, dim=0).contiguous()
+
+    feature_banks = [torch.zeros_like(feature_bank)
+                     for i in range(mpu.get_data_parallel_world_size())]
+    torch.distributed.all_gather(feature_banks,
+                                 feature_bank,
+                                 group=mpu.get_data_parallel_group())
+
+    assert torch.all(torch.eq(feature_banks[mpu.get_data_parallel_rank()],
+                              feature_bank))
+
+    feature_labels = [torch.zeros_like(feature_label)
+                      for i in range(mpu.get_data_parallel_world_size())]
+    torch.distributed.all_gather(feature_labels,
+                                 feature_label,
+                                 group=mpu.get_data_parallel_group())
+
+    # [D, N]
+    feature_banks = torch.cat(feature_banks, dim=0).t().contiguous()
+    # [N]
+    feature_labels = torch.cat(feature_labels, dim=0).contiguous()
+    print_rank_0("feature_banks size is {}".format(feature_banks.size()))
+    print_rank_0("feature labels size is {}".format(feature_labels.size()))
+
+    _FEATURE_BANK = (feature_banks, feature_labels, classes)
+
+
+def get_feature_bank():
+    global _FEATURE_BANK
+    assert _FEATURE_BANK is not None
+    return _FEATURE_BANK
+
+
+# knn monitor as in InstDisc https://arxiv.org/abs/1805.01978
+# implementation follows http://github.com/zhirongw/lemniscate.pytorch and
+# https://github.com/leftthomas/SimCLR
+def knn_predict(feature, feature_bank, feature_labels, classes, knn_k, knn_t):
+    # compute cos similarity between each feature vector and feature bank ---> [B, N]
+    sim_matrix = torch.mm(feature, feature_bank)
+    # [B, K]
+    sim_weight, sim_indices = sim_matrix.topk(k=knn_k, dim=-1)
+    # [B, K]
+    sim_labels = torch.gather(feature_labels.expand(feature.size(0), -1),
+                              dim=-1,
+                              index=sim_indices)
+    sim_weight = (sim_weight / knn_t).exp()
+
+    # counts for each class
+    one_hot_label = torch.zeros(feature.size(0) * knn_k,
+                                classes,
+                                device=sim_labels.device)
+    # [B*K, C]
+    one_hot_label = one_hot_label.scatter(dim=-1,
+                                          index=sim_labels.view(-1, 1),
+                                          value=1.0)
+    # weighted score ---> [B, C]
+    pred_scores = torch.sum(
+            one_hot_label.view(feature.size(0), -1, classes) * sim_weight.unsqueeze(dim=-1),
+            dim=1)
+
+    pred_labels = pred_scores.argsort(dim=-1, descending=True)
+    return pred_labels

megatron/model/vision/mit_backbone.py

+# ---------------------------------------------------------------
+# Copyright (c) 2021, NVIDIA Corporation. All rights reserved.
+#
+# This work is licensed under the NVIDIA Source Code License
+# found in the LICENSE file in the root directory of this 
+# source tree.
+# ---------------------------------------------------------------
+import math
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+from functools import partial
+from torch.nn.init import trunc_normal_
+from megatron.model.transformer import DropPath
+from megatron.model import LayerNorm
+
+
+class Mlp(nn.Module):
+    def __init__(self,
+                 in_features,
+                 hidden_features=None,
+                 out_features=None,
+                 act_layer=nn.GELU,
+                 drop=0.):
+        super().__init__()
+        out_features = out_features or in_features
+        hidden_features = hidden_features or in_features
+        self.fc1 = nn.Linear(in_features, hidden_features)
+        self.dwconv = DWConv(hidden_features)
+        self.act = act_layer()
+        self.fc2 = nn.Linear(hidden_features, out_features)
+        self.drop = nn.Dropout(drop)
+
+        self.apply(self._init_weights)
+
+    def _init_weights(self, m):
+        if isinstance(m, nn.Linear):
+            trunc_normal_(m.weight, std=.02)
+            if isinstance(m, nn.Linear) and m.bias is not None:
+                nn.init.constant_(m.bias, 0)
+        elif isinstance(m, nn.LayerNorm):
+            nn.init.constant_(m.bias, 0)
+            nn.init.constant_(m.weight, 1.0)
+        elif isinstance(m, nn.Conv2d):
+            fan_out = m.kernel_size[0] * m.kernel_size[1] * m.out_channels
+            fan_out //= m.groups
+            m.weight.data.normal_(0, math.sqrt(2.0 / fan_out))
+            if m.bias is not None:
+                m.bias.data.zero_()
+
+    def forward(self, x, H, W):
+        x = self.fc1(x)
+        x = self.dwconv(x, H, W)
+        x = self.act(x)
+        x = self.drop(x)
+        x = self.fc2(x)
+        x = self.drop(x)
+        return x
+
+
+class Attention(nn.Module):
+    def __init__(self,
+                 dim,
+                 num_heads=8,
+                 qkv_bias=False,
+                 qk_scale=None,
+                 attn_drop=0.,
+                 proj_drop=0.,
+                 sr_ratio=1):
+        super().__init__()
+        assert dim % num_heads == 0, f"dim {dim} should be divided by num_heads {num_heads}."
+
+        self.dim = dim
+        self.num_heads = num_heads
+        head_dim = dim // num_heads
+        self.scale = qk_scale or head_dim ** -0.5
+
+        self.q = nn.Linear(dim, dim, bias=qkv_bias)
+        self.kv = nn.Linear(dim, dim * 2, bias=qkv_bias)
+        self.attn_drop = nn.Dropout(attn_drop)
+        self.proj = nn.Linear(dim, dim)
+        self.proj_drop = nn.Dropout(proj_drop)
+
+        self.sr_ratio = sr_ratio
+        if sr_ratio > 1:
+            self.sr = nn.Conv2d(dim, dim, kernel_size=sr_ratio, stride=sr_ratio)
+            self.norm = LayerNorm(dim)
+
+        self.apply(self._init_weights)
+
+    def _init_weights(self, m):
+        if isinstance(m, nn.Linear):
+            trunc_normal_(m.weight, std=.02)
+            if isinstance(m, nn.Linear) and m.bias is not None:
+                nn.init.constant_(m.bias, 0)
+        elif isinstance(m, nn.LayerNorm):
+            nn.init.constant_(m.bias, 0)
+            nn.init.constant_(m.weight, 1.0)
+        elif isinstance(m, nn.Conv2d):
+            fan_out = m.kernel_size[0] * m.kernel_size[1] * m.out_channels
+            fan_out //= m.groups
+            m.weight.data.normal_(0, math.sqrt(2.0 / fan_out))
+            if m.bias is not None:
+                m.bias.data.zero_()
+
+    def forward(self, x, H, W):
+        B, N, C = x.shape
+        q = self.q(x).reshape(B, N, self.num_heads, C // self.num_heads).permute(0, 2, 1, 3)
+
+        if self.sr_ratio > 1:
+            x_ = x.permute(0, 2, 1).reshape(B, C, H, W)
+            x_ = self.sr(x_).reshape(B, C, -1).permute(0, 2, 1)
+            x_ = self.norm(x_)
+            kv = self.kv(x_).reshape(B, -1, 2, self.num_heads, C // self.num_heads).permute(2, 0, 3, 1, 4)
+        else:
+            kv = self.kv(x).reshape(B, -1, 2, self.num_heads, C // self.num_heads).permute(2, 0, 3, 1, 4)
+        k, v = kv[0], kv[1]
+
+        attn = (q @ k.transpose(-2, -1)) * self.scale
+        attn = attn.softmax(dim=-1)
+        attn = self.attn_drop(attn)
+
+        x = (attn @ v).transpose(1, 2).reshape(B, N, C)
+        x = self.proj(x)
+        x = self.proj_drop(x)
+
+        return x
+
+
+class Block(nn.Module):
+
+    def __init__(self, dim, num_heads, mlp_ratio=4., qkv_bias=False, qk_scale=None, drop=0., attn_drop=0.,
+                 drop_path=0., act_layer=nn.GELU, norm_layer=LayerNorm, sr_ratio=1):
+        super().__init__()
+        self.norm1 = norm_layer(dim)
+        self.attn = Attention(
+            dim,
+            num_heads=num_heads, qkv_bias=qkv_bias, qk_scale=qk_scale,
+            attn_drop=attn_drop, proj_drop=drop, sr_ratio=sr_ratio)
+        # NOTE: drop path for stochastic depth, we shall see if this is better than dropout here
+        self.drop_path = DropPath(drop_path) if drop_path > 0. else nn.Identity()
+        self.norm2 = norm_layer(dim)
+        mlp_hidden_dim = int(dim * mlp_ratio)
+        self.mlp = Mlp(in_features=dim, hidden_features=mlp_hidden_dim, act_layer=act_layer, drop=drop)
+
+        self.apply(self._init_weights)
+
+    def _init_weights(self, m):
+        if isinstance(m, nn.Linear):
+            trunc_normal_(m.weight, std=.02)
+            if isinstance(m, nn.Linear) and m.bias is not None:
+                nn.init.constant_(m.bias, 0)
+        elif isinstance(m, nn.LayerNorm):
+            nn.init.constant_(m.bias, 0)
+            nn.init.constant_(m.weight, 1.0)
+        elif isinstance(m, nn.Conv2d):
+            fan_out = m.kernel_size[0] * m.kernel_size[1] * m.out_channels
+            fan_out //= m.groups
+            m.weight.data.normal_(0, math.sqrt(2.0 / fan_out))
+            if m.bias is not None:
+                m.bias.data.zero_()
+
+    def forward(self, x, H, W):
+        x = x + self.drop_path(self.attn(self.norm1(x), H, W))
+        x = x + self.drop_path(self.mlp(self.norm2(x), H, W))
+
+        return x
+
+
+class OverlapPatchEmbed(nn.Module):
+    """ Image to Patch Embedding
+    """
+
+    def __init__(self, img_size=224, patch_size=7, stride=4, in_chans=3, embed_dim=768):
+        super().__init__()
+        img_size = (img_size, img_size)
+        patch_size = (patch_size, patch_size)
+
+        self.proj = nn.Conv2d(in_chans, embed_dim, kernel_size=patch_size, stride=stride,
+                              padding=(patch_size[0] // 2, patch_size[1] // 2))
+        self.norm = LayerNorm(embed_dim)
+
+        self.apply(self._init_weights)
+
+    def _init_weights(self, m):
+        if isinstance(m, nn.Linear):
+            trunc_normal_(m.weight, std=.02)
+            if isinstance(m, nn.Linear) and m.bias is not None:
+                nn.init.constant_(m.bias, 0)
+        elif isinstance(m, nn.LayerNorm):
+            nn.init.constant_(m.bias, 0)
+            nn.init.constant_(m.weight, 1.0)
+        elif isinstance(m, nn.Conv2d):
+            fan_out = m.kernel_size[0] * m.kernel_size[1] * m.out_channels
+            fan_out //= m.groups
+            m.weight.data.normal_(0, math.sqrt(2.0 / fan_out))
+            if m.bias is not None:
+                m.bias.data.zero_()
+
+    def forward(self, x):
+        x = self.proj(x)
+        _, _, H, W = x.shape
+        x = x.flatten(2).transpose(1, 2)
+        x = self.norm(x)
+
+        return x, H, W
+
+
+class MixVisionTransformer(nn.Module):
+    def __init__(self, img_size=224, patch_size=16, in_chans=3, num_classes=1000, embed_dims=[64, 128, 256, 512],
+                 num_heads=[1, 2, 4, 8], mlp_ratios=[4, 4, 4, 4], qkv_bias=False, qk_scale=None, drop_rate=0.,
+                 attn_drop_rate=0., drop_path_rate=0., norm_layer=LayerNorm,
+                 depths=[3, 4, 6, 3], sr_ratios=[8, 4, 2, 1], output_avg=False):
+        super().__init__()
+        self.num_classes = num_classes
+        self.depths = depths
+        self.output_avg = output_avg
+
+        # patch_embed
+        self.patch_embed1 = OverlapPatchEmbed(img_size=img_size, patch_size=7, stride=4, in_chans=in_chans,
+                                              embed_dim=embed_dims[0])
+        self.patch_embed2 = OverlapPatchEmbed(img_size=img_size // 4, patch_size=3, stride=2, in_chans=embed_dims[0],
+                                              embed_dim=embed_dims[1])
+        self.patch_embed3 = OverlapPatchEmbed(img_size=img_size // 8, patch_size=3, stride=2, in_chans=embed_dims[1],
+                                              embed_dim=embed_dims[2])
+        self.patch_embed4 = OverlapPatchEmbed(img_size=img_size // 16, patch_size=3, stride=2, in_chans=embed_dims[2],
+                                              embed_dim=embed_dims[3])
+
+        # transformer encoder
+        dpr = [x.item() for x in torch.linspace(0, drop_path_rate, sum(depths))]  # stochastic depth decay rule
+        cur = 0
+        self.block1 = nn.ModuleList([Block(
+            dim=embed_dims[0], num_heads=num_heads[0], mlp_ratio=mlp_ratios[0], qkv_bias=qkv_bias, qk_scale=qk_scale,
+            drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[cur + i], norm_layer=norm_layer,
+            sr_ratio=sr_ratios[0])
+            for i in range(depths[0])])
+        self.norm1 = norm_layer(embed_dims[0])
+
+        cur += depths[0]
+        self.block2 = nn.ModuleList([Block(
+            dim=embed_dims[1], num_heads=num_heads[1], mlp_ratio=mlp_ratios[1], qkv_bias=qkv_bias, qk_scale=qk_scale,
+            drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[cur + i], norm_layer=norm_layer,
+            sr_ratio=sr_ratios[1])
+            for i in range(depths[1])])
+        self.norm2 = norm_layer(embed_dims[1])
+
+        cur += depths[1]
+        self.block3 = nn.ModuleList([Block(
+            dim=embed_dims[2], num_heads=num_heads[2], mlp_ratio=mlp_ratios[2], qkv_bias=qkv_bias, qk_scale=qk_scale,
+            drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[cur + i], norm_layer=norm_layer,
+            sr_ratio=sr_ratios[2])
+            for i in range(depths[2])])
+        self.norm3 = norm_layer(embed_dims[2])
+
+        cur += depths[2]
+        self.block4 = nn.ModuleList([Block(
+            dim=embed_dims[3], num_heads=num_heads[3], mlp_ratio=mlp_ratios[3], qkv_bias=qkv_bias, qk_scale=qk_scale,
+            drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[cur + i], norm_layer=norm_layer,
+            sr_ratio=sr_ratios[3])
+            for i in range(depths[3])])
+        self.norm4 = norm_layer(embed_dims[3])
+
+        self.apply(self._init_weights)
+
+    def _init_weights(self, m):
+        if isinstance(m, nn.Linear):
+            trunc_normal_(m.weight, std=.02)
+            if isinstance(m, nn.Linear) and m.bias is not None:
+                nn.init.constant_(m.bias, 0)
+        elif isinstance(m, nn.LayerNorm):
+            nn.init.constant_(m.bias, 0)
+            nn.init.constant_(m.weight, 1.0)
+        elif isinstance(m, nn.Conv2d):
+            fan_out = m.kernel_size[0] * m.kernel_size[1] * m.out_channels
+            fan_out //= m.groups
+            m.weight.data.normal_(0, math.sqrt(2.0 / fan_out))
+            if m.bias is not None:
+                m.bias.data.zero_()
+
+    def reset_drop_path(self, drop_path_rate):
+        dpr = [x.item() for x in torch.linspace(0, drop_path_rate, sum(self.depths))]
+        cur = 0
+        for i in range(self.depths[0]):
+            self.block1[i].drop_path.drop_prob = dpr[cur + i]
+
+        cur += self.depths[0]
+        for i in range(self.depths[1]):
+            self.block2[i].drop_path.drop_prob = dpr[cur + i]
+
+        cur += self.depths[1]
+        for i in range(self.depths[2]):
+            self.block3[i].drop_path.drop_prob = dpr[cur + i]
+
+        cur += self.depths[2]
+        for i in range(self.depths[3]):
+            self.block4[i].drop_path.drop_prob = dpr[cur + i]
+
+    def freeze_patch_emb(self):
+        self.patch_embed1.requires_grad = False
+
+    def forward_features(self, x):
+        B = x.shape[0]
+        outs = []
+
+        # stage 1
+        x, H, W = self.patch_embed1(x)
+        for i, blk in enumerate(self.block1):
+            x = blk(x, H, W)
+        x = self.norm1(x)
+        x = x.reshape(B, H, W, -1).permute(0, 3, 1, 2).contiguous()
+        outs.append(x)
+
+        # stage 2
+        x, H, W = self.patch_embed2(x)
+        for i, blk in enumerate(self.block2):
+            x = blk(x, H, W)
+        x = self.norm2(x)
+        x = x.reshape(B, H, W, -1).permute(0, 3, 1, 2).contiguous()
+        outs.append(x)
+
+        # stage 3
+        x, H, W = self.patch_embed3(x)
+        for i, blk in enumerate(self.block3):
+            x = blk(x, H, W)
+        x = self.norm3(x)
+        x = x.reshape(B, H, W, -1).permute(0, 3, 1, 2).contiguous()
+        outs.append(x)
+
+        # stage 4
+        x, H, W = self.patch_embed4(x)
+        for i, blk in enumerate(self.block4):
+            x = blk(x, H, W)
+        x = self.norm4(x)
+        if not self.output_avg:
+            x = x.reshape(B, H, W, -1).permute(0, 3, 1, 2).contiguous()
+        outs.append(x)
+
+        return outs
+
+    def forward(self, x):
+        x = self.forward_features(x)
+    
+        if self.output_avg:
+            x = x[3].mean(dim=1)
+
+        return x
+
+
+class DWConv(nn.Module):
+    def __init__(self, dim=768):
+        super(DWConv, self).__init__()
+        self.dwconv = nn.Conv2d(dim, dim, 3, 1, 1, bias=True, groups=dim)
+
+    def forward(self, x, H, W):
+        B, N, C = x.shape
+        x = x.transpose(1, 2).view(B, C, H, W)
+        x = self.dwconv(x)
+        x = x.flatten(2).transpose(1, 2)
+
+        return x
+
+class mit_b0(MixVisionTransformer):
+    def __init__(self, **kwargs):
+        super(mit_b0, self).__init__(
+            patch_size=4, embed_dims=[32, 64, 160, 256], num_heads=[1, 2, 5, 8], mlp_ratios=[4, 4, 4, 4],
+            qkv_bias=True, norm_layer=partial(LayerNorm, eps=1e-6), depths=[2, 2, 2, 2], sr_ratios=[8, 4, 2, 1],
+            drop_rate=0.0, drop_path_rate=0.1)
+
+
+class mit_b1(MixVisionTransformer):
+    def __init__(self, **kwargs):
+        super(mit_b1, self).__init__(
+            patch_size=4, embed_dims=[64, 128, 320, 512], num_heads=[1, 2, 5, 8], mlp_ratios=[4, 4, 4, 4],
+            qkv_bias=True, norm_layer=partial(LayerNorm, eps=1e-6), depths=[2, 2, 2, 2], sr_ratios=[8, 4, 2, 1],
+            drop_rate=0.0, drop_path_rate=0.1)
+
+
+class mit_b2(MixVisionTransformer):
+    def __init__(self, **kwargs):
+        super(mit_b2, self).__init__(
+            patch_size=4, embed_dims=[64, 128, 320, 512], num_heads=[1, 2, 5, 8], mlp_ratios=[4, 4, 4, 4],
+            qkv_bias=True, norm_layer=partial(LayerNorm, eps=1e-6), depths=[3, 4, 6, 3], sr_ratios=[8, 4, 2, 1],
+            drop_rate=0.0, drop_path_rate=0.1)
+
+ 
+class mit_b3(MixVisionTransformer):
+    def __init__(self, **kwargs):
+        super(mit_b3, self).__init__(
+            patch_size=4, embed_dims=[64, 128, 320, 512], num_heads=[1, 2, 5, 8], mlp_ratios=[4, 4, 4, 4],
+            qkv_bias=True, norm_layer=partial(LayerNorm, eps=1e-6), depths=[3, 4, 18, 3], sr_ratios=[8, 4, 2, 1],
+            drop_rate=0.0, drop_path_rate=0.1)
+
+class mit_b3_avg(MixVisionTransformer):
+    def __init__(self, drop_path_rate=0.1, **kwargs):
+        super(mit_b3_avg, self).__init__(
+            patch_size=4, embed_dims=[64, 128, 320, 512], num_heads=[1, 2, 5, 8], mlp_ratios=[4, 4, 4, 4],
+            qkv_bias=True, norm_layer=partial(LayerNorm, eps=1e-6), depths=[3, 4, 18, 3], sr_ratios=[8, 4, 2, 1],
+            drop_rate=0.0, drop_path_rate=drop_path_rate, output_avg=True)
+
+class mit_b4(MixVisionTransformer):
+    def __init__(self, **kwargs):
+        super(mit_b4, self).__init__(
+            patch_size=4, embed_dims=[64, 128, 320, 512], num_heads=[1, 2, 5, 8], mlp_ratios=[4, 4, 4, 4],
+            qkv_bias=True, norm_layer=partial(LayerNorm, eps=1e-6), depths=[3, 8, 27, 3], sr_ratios=[8, 4, 2, 1],
+            drop_rate=0.0, drop_path_rate=0.1)
+
+class mit_b5(MixVisionTransformer):
+    def __init__(self, **kwargs):
+        super(mit_b5, self).__init__(
+            patch_size=4, embed_dims=[64, 128, 320, 512], num_heads=[1, 2, 5, 8], mlp_ratios=[4, 4, 4, 4],
+            qkv_bias=True, norm_layer=partial(LayerNorm, eps=1e-6), depths=[3, 6, 40, 3], sr_ratios=[8, 4, 2, 1],
+            drop_rate=0.0, drop_path_rate=0.1)
+
+class mit_b5_avg(MixVisionTransformer):
+    def __init__(self, drop_path_rate=0.1, **kwargs):
+        super(mit_b5_avg, self).__init__(
+            patch_size=4, embed_dims=[64, 128, 320, 512], num_heads=[1, 2, 5, 8], mlp_ratios=[4, 4, 4, 4],
+            qkv_bias=True, norm_layer=partial(LayerNorm, eps=1e-6), depths=[3, 6, 40, 3], sr_ratios=[8, 4, 2, 1],
+            drop_rate=0.0, drop_path_rate=drop_path_rate, output_avg=True)
+

megatron/model/vision/utils.py

+import warnings
+import torch
+import torch.nn.functional as F
+
+
+def resize(input,
+           size=None,
+           scale_factor=None,
+           mode='nearest',
+           align_corners=None,
+           warning=True):
+    if warning:
+        if size is not None and align_corners:
+            input_h, input_w = tuple(int(x) for x in input.shape[2:])
+            output_h, output_w = tuple(int(x) for x in size)
+            if output_h > input_h or output_w > output_h:
+                if ((output_h > 1 and output_w > 1 and input_h > 1
+                     and input_w > 1) and (output_h - 1) % (input_h - 1)
+                        and (output_w - 1) % (input_w - 1)):
+                    warnings.warn(
+                        f'When align_corners={align_corners}, '
+                        'the output would more aligned if '
+                        f'input size {(input_h, input_w)} is `x+1` and '
+                        f'out size {(output_h, output_w)} is `nx+1`')
+    if isinstance(size, torch.Size):
+        size = tuple(int(x) for x in size)
+    return F.interpolate(input, size, scale_factor, mode, align_corners)

megatron/model/vit_model.py → megatron/model/vision/vit_backbone.py

@@ -18,16 +18,19 @@
 import math
 import einops
 import torch
+import apex
 import torch.nn.functional as F
 from megatron import get_args
+from megatron.model import LayerNorm
 from megatron.model.transformer import ParallelTransformer
 from megatron.model.utils import (
     get_linear_layer,
     init_method_normal,
     scaled_init_method_normal,
 )
-from .module import MegatronModule
+from megatron.model.module import MegatronModule
 
+CLASS_TOKEN_LENGTH = 8
 
 class VitMlpHead(MegatronModule):
     """Pooler layer.
@@ -44,19 +47,26 @@ class VitMlpHead(MegatronModule):
     def __init__(self, hidden_size, num_classes):
         super(VitMlpHead, self).__init__()
         self.dense_in = torch.nn.Linear(hidden_size, hidden_size)
+        self.relu = torch.nn.ReLU()
         self.dense_out = torch.nn.Linear(hidden_size, num_classes)
         torch.nn.init.constant_(self.dense_out.bias, -10)
 
-    def forward(self, hidden_states, sequence_index=0):
-        # hidden_states: [b, s, h]
+    def forward(self, hidden_states):
+        # hidden_states: [b, 1, h]
         # sequence_index: index of the token to pool.
-        hidden_state = hidden_states[:, sequence_index, :]
-        dense_in_result = self.dense_in(hidden_state)
+        dense_in_result = self.dense_in(hidden_states)
         tanh_result = torch.tanh(dense_in_result)
         dense_out_result = self.dense_out(tanh_result)
         return dense_out_result
 
 
+def isPerfectSquare(x):
+    if(x >= 0):
+        sr = math.sqrt(x)
+        return (int(sr) * int(sr) == x)
+    return False
+
+
 def twod_interpolate_position_embeddings_hook(
     state_dict,
     prefix,
@@ -68,66 +78,78 @@ def twod_interpolate_position_embeddings_hook(
 ):
 
     args = get_args()
-    num_patches_per_dim = args.img_dim // args.patch_dim
-    num_patches = num_patches_per_dim ** 2
-    seq_length = num_patches + 1
+    num_patches_per_dim_h = args.img_h // args.patch_dim
+    num_patches_per_dim_w = args.img_w // args.patch_dim
+    num_patches = num_patches_per_dim_h * num_patches_per_dim_w
     hidden_size = args.hidden_size
 
     key = prefix + "weight"
-    # import pdb
-    # pdb.set_trace()
+
     assert key in state_dict
     if key in state_dict:
         input_param = state_dict[key]
 
+        input_seq_len = input_param.shape[0]
+        assert(isPerfectSquare(input_seq_len) or isPerfectSquare(input_seq_len - CLASS_TOKEN_LENGTH))
+        input_has_class_token = not isPerfectSquare(input_seq_len)
+        num_tok_input = input_seq_len - CLASS_TOKEN_LENGTH if input_has_class_token else input_seq_len
+        num_tok_output = num_patches
+        output_has_class_token = args.class_token_present
+
+        # update input_param and load it to state_dict[key]
+        if input_has_class_token:
+            input_param_tok = input_param[:CLASS_TOKEN_LENGTH, :]
+            input_param_grid = input_param[CLASS_TOKEN_LENGTH:, :]
+        else:
+            input_param_tok = torch.zeros(CLASS_TOKEN_LENGTH, hidden_size)
+            input_param_grid = input_param
+
         assert input_param.shape[1] == hidden_size
-        if input_param.shape[0] != seq_length:
-            # update input_param and load it to state_dict[key]
-
-            num_tok_input = input_param.shape[0] - 1
-            num_tok_new = seq_length - 1
-            input_param_tok, input_param_grid = (
-                input_param[:1, :],
-                input_param[1:, :],
-            )
+
+        if num_tok_input != num_tok_output:
 
             gs_input = int(math.sqrt(num_tok_input))
-            gs_new = int(math.sqrt(num_tok_new))
+            gs_new = (num_patches_per_dim_h, num_patches_per_dim_w)
 
             input_param_grid = input_param_grid.transpose(0, 1).contiguous()
             input_param_grid = input_param_grid.reshape(
                 (1, -1, gs_input, gs_input)
             )
             input_param_grid = input_param_grid.float()
-            scale_factor = gs_new / gs_input
+            scale_factor = (gs_new[0] / gs_input, gs_new[1] / gs_input)
 
             input_param_grid = F.interpolate(
                 input_param_grid, scale_factor=scale_factor, mode="bilinear"
             )
 
             input_param_grid = input_param_grid.half()
-            input_param_grid = input_param_grid.reshape((-1, gs_new * gs_new))
+            input_param_grid = input_param_grid.reshape((-1, num_tok_output))
             input_param_grid = input_param_grid.transpose(0, 1).contiguous()
 
             assert input_param_grid.shape[1] == hidden_size
-            input_param = torch.cat((input_param_tok, input_param_grid), dim=0)
-            assert (
-                input_param.shape[0] == seq_length
-                and input_param.shape[1] == hidden_size
-            )
 
-            state_dict[key] = input_param
+        input_param = input_param_grid
+        assert (
+            input_param.shape[0] == num_tok_output
+            and input_param.shape[1] == hidden_size
+        )
+
+        if output_has_class_token:
+            input_param = torch.cat((input_param_tok, input_param), dim=0)
+
+        state_dict[key] = input_param
 
 
-class VitModel(MegatronModule):
+class VitBackbone(MegatronModule):
     """Vision Transformer Model."""
 
-    def __init__(self, 
-                 num_classes,
-                 finetune=False,
+    def __init__(self,
                  pre_process=True,
-                 post_process=True):
-        super(VitModel, self).__init__(share_word_embeddings=False)
+                 post_process=True,
+                 class_token=True,
+                 single_token_output=False,
+                 drop_path_rate=0.0):
+        super(VitBackbone, self).__init__(share_word_embeddings=False)
         args = get_args()
 
         self.fp16_lm_cross_entropy = args.fp16_lm_cross_entropy
@@ -142,25 +164,34 @@ class VitModel(MegatronModule):
 
         self.pre_process = pre_process
         self.post_process = post_process
+        self.class_token = class_token
         self.hidden_size = args.hidden_size
-        self.num_classes = num_classes
         self.patch_dim = args.patch_dim
-        self.img_dim = args.img_dim
-        self.finetune = finetune
-
-        assert self.img_dim % self.patch_dim == 0
-        self.num_patches_per_dim = self.img_dim // self.patch_dim
-        self.num_patches = self.num_patches_per_dim ** 2
-        self.seq_length = self.num_patches + 1
+        self.img_h = args.img_h
+        self.img_w = args.img_w
+        self.micro_batch_size = args.micro_batch_size
+        self.single_token_output = single_token_output
+        self.drop_path_rate = drop_path_rate
+
+        assert self.img_h % self.patch_dim == 0
+        assert self.img_w % self.patch_dim == 0
+        self.num_patches_per_dim_h = self.img_h // self.patch_dim
+        self.num_patches_per_dim_w = self.img_w // self.patch_dim
+        self.num_patches = self.num_patches_per_dim_h * self.num_patches_per_dim_w
+        self.seq_length = self.num_patches + (CLASS_TOKEN_LENGTH if self.class_token else 0)
         self.flatten_dim = self.patch_dim * self.patch_dim * args.num_channels
+        self.input_tensor = None
+        self.position_ids = None
 
         if self.pre_process:
             # cls_token
-            self.cls_token = torch.nn.Parameter(
-                torch.randn(1, 1, self.hidden_size)
-            )
-            torch.nn.init.zeros_(self.cls_token)
-
+            if self.class_token:
+                self.cls_token = torch.nn.Parameter(
+                    torch.randn(1, CLASS_TOKEN_LENGTH, self.hidden_size)
+                )
+                torch.nn.init.zeros_(self.cls_token)
+            self.position_ids = torch.arange(self.seq_length).expand(1, -1).cuda()
+            
             # Linear encoder
             self.linear_encoder = torch.nn.Linear(
                 self.flatten_dim, self.hidden_size
@@ -173,8 +204,8 @@ class VitModel(MegatronModule):
             init_method_normal(args.init_method_std)(
                 self.position_embeddings.weight
             )
-            self.position_ids = torch.arange(self.seq_length).expand(1, -1).cuda()
 
+            args.class_token_present = self.class_token
             self.position_embeddings._register_load_state_dict_pre_hook(
                 twod_interpolate_position_embeddings_hook
             )
@@ -183,21 +214,13 @@ class VitModel(MegatronModule):
 
         # Transformer
         self.transformer = ParallelTransformer(
-            self.init_method, 
+            self.init_method,
             self.scaled_init_method,
             pre_process=self.pre_process,
-            post_process=self.post_process
+            post_process=self.post_process,
+            drop_path_rate=self.drop_path_rate
         )
 
-        if self.post_process:
-            # MLP head
-            if not self.finetune:
-                self.mlp_head = VitMlpHead(self.hidden_size, self.num_classes)
-            else:
-                self.class_head = get_linear_layer(
-                    self.hidden_size, num_classes, torch.nn.init.zeros_
-                )
-
     def set_input_tensor(self, input_tensor):
         """See megatron.model.transformer.set_input_tensor()"""
         self.transformer.set_input_tensor(input_tensor)
@@ -214,21 +237,22 @@ class VitModel(MegatronModule):
 
             assert rearranged_input.dtype == torch.half
             encoder_output = self.linear_encoder(rearranged_input)
-            cls_tokens = self.cls_token.expand(encoder_output.shape[0], -1, -1)
-            concatenated_tokens = torch.cat((cls_tokens, encoder_output), dim=1)
+
+            concatenated_tokens = encoder_output
+            if self.class_token:
+                cls_tokens = self.cls_token.expand(encoder_output.shape[0], -1, -1)
+                concatenated_tokens = torch.cat((cls_tokens, encoder_output), dim=1)
 
             token_embeddings = concatenated_tokens + \
-                self.position_embeddings(self.position_ids)
+                    self.position_embeddings(self.position_ids[:, :concatenated_tokens.shape[1]])
             hidden_states = self.embedding_dropout(token_embeddings)
         else:
             hidden_states = input
 
         hidden_states = self.transformer(hidden_states, None)
 
-        if self.post_process:
-            if not self.finetune:
-                hidden_states = self.mlp_head(hidden_states)
-            else:
-                hidden_states = self.class_head(hidden_states[:, 0, :])
+        if self.single_token_output:
+            hidden_states = hidden_states[:,0,:]
 
         return hidden_states
+

megatron/mpu/__init__.py

@@ -25,6 +25,7 @@ from .initialize import get_data_parallel_group
 from .initialize import get_data_parallel_rank
 from .initialize import get_data_parallel_world_size
 from .initialize import get_embedding_group
+from .initialize import get_position_embedding_group
 from .initialize import get_model_parallel_group
 from .initialize import get_tensor_model_parallel_group
 from .initialize import get_pipeline_model_parallel_group
@@ -32,10 +33,12 @@ from .initialize import get_tensor_model_parallel_rank, set_tensor_model_paralle
 from .initialize import get_pipeline_model_parallel_rank, set_pipeline_model_parallel_rank
 from .initialize import is_pipeline_first_stage, is_pipeline_last_stage
 from .initialize import is_rank_in_embedding_group
+from .initialize import is_rank_in_position_embedding_group
 from .initialize import is_pipeline_stage_before_split, is_pipeline_stage_after_split
 from .initialize import is_pipeline_stage_at_split
 from .initialize import get_num_layers
 from .initialize import get_tensor_model_parallel_src_rank
+from .initialize import get_data_parallel_src_rank
 from .initialize import get_pipeline_model_parallel_first_rank
 from .initialize import get_pipeline_model_parallel_last_rank
 from .initialize import get_pipeline_model_parallel_next_rank
@@ -63,6 +66,9 @@ from .random import get_cuda_rng_tracker
 from .random import model_parallel_cuda_manual_seed
 from .random import gather_split_1d_tensor
 from .random import split_tensor_into_1d_equal_chunks
+from .random import make_viewless_tensor
+from .random import assert_viewless_tensor
+from .random import safely_set_viewless_tensor_data
 
 from .utils import divide
 from .utils import split_tensor_along_last_dim