sequence parallelism for embedding dropout and last linear layer + memory optimizations

megatron/model/language_model.py

@@ -37,7 +37,7 @@ def parallel_lm_logits(input_, word_embeddings_weight, parallel_output,
         input_parallel = input_
         model_parallel = mpu.get_tensor_model_parallel_world_size() > 1
         async_grad_allreduce = args.async_tensor_model_parallel_allreduce and \
-            model_parallel
+            model_parallel and not args.model_parallel_memory_opt
     else:
         input_parallel = mpu.copy_to_tensor_model_parallel_region(input_)
         async_grad_allreduce = False
@@ -46,7 +46,7 @@ def parallel_lm_logits(input_, word_embeddings_weight, parallel_output,
     logits_parallel = mpu.LinearWithGradAccumulationAndAsyncCommunication.apply(
         input_parallel, word_embeddings_weight, bias,
         args.gradient_accumulation_fusion,
-        async_grad_allreduce, None)
+        async_grad_allreduce, args.model_parallel_memory_opt)
     # Gather if needed.
 
     if parallel_output:
@@ -170,6 +170,8 @@ class Embedding(MegatronModule):
         else:
             self.tokentype_embeddings = None
 
+        self.fp32_residual_connection = args.fp32_residual_connection 
+        self.model_parallel_memory_opt = args.model_parallel_memory_opt
         # Embeddings dropout
         self.embedding_dropout = torch.nn.Dropout(embedding_dropout_prob)
 
@@ -211,7 +213,22 @@ class Embedding(MegatronModule):
         else:
             assert self.tokentype_embeddings is None
 
+        # Data format change to avoid explicit tranposes : [b s h] --> [s b h].
+        # If the input flag for fp32 residual connection is set, convert for float.
+        if self.fp32_residual_connection:
+            embeddings = embeddings.transpose(0, 1).contiguous().float()
+        # Otherwise, leave it as is.
+        else:
+            embeddings = embeddings.transpose(0, 1).contiguous()
+
+        if self.model_parallel_memory_opt:
+            embeddings = mpu.scatter_to_sequence_parallel_region(embeddings)
+            
         # Dropout.
+        if self.model_parallel_memory_opt:
+            with mpu.get_cuda_rng_tracker().fork():
+                embeddings = self.embedding_dropout(embeddings)
+        else:
             embeddings = self.embedding_dropout(embeddings)
 
         return embeddings

megatron/model/transformer.py

@@ -18,7 +18,7 @@ import math
 import torch
 import torch.nn.functional as F
 
-from megatron import get_args
+from megatron import get_timers, get_args, print_rank_last, print_rank_0
 from megatron import mpu
 from .module import MegatronModule
 from megatron.model.enums import AttnMaskType, ModelType, LayerType, AttnType
@@ -27,6 +27,8 @@ 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
 
+_MATMUL_INPUT = None
+
 """ We use the following notation throughout this file:
      h: hidden size
      n: number of attention heads
@@ -42,7 +44,6 @@ 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).
@@ -189,6 +190,17 @@ class CoreAttention(MegatronModule):
                                                     world_size)
         self.hidden_size_per_attention_head = mpu.divide(
             projection_size, args.num_attention_heads)
+        self.num_attention_heads_per_partition = mpu.divide(
+            args.num_attention_heads, world_size)
+
+        global _MATMUL_INPUT
+        if _MATMUL_INPUT is None:
+            _MATMUL_INPUT = torch.empty(
+                args.micro_batch_size * self.num_attention_heads_per_partition,
+                args.seq_length,
+                args.seq_length,
+                dtype=torch.bfloat16,
+                device=torch.cuda.current_device())
         
         coeff = None
         self.norm_factor = math.sqrt(self.hidden_size_per_attention_head)
@@ -230,16 +242,19 @@ class CoreAttention(MegatronModule):
                                    output_size[0] * output_size[1], -1)
 
         # preallocting result tensor: [b * np, sq, sk]
-        matmul_result = torch.empty(
-            output_size[0]*output_size[1],
-            output_size[2],
-            output_size[3],
-            dtype=query_layer.dtype,
-            device=torch.cuda.current_device())
+        #matmul_result = torch.empty(
+        #    output_size[0]*output_size[1],
+        #    output_size[2],
+        #    output_size[3],
+        #    dtype=query_layer.dtype,
+        #    device=torch.cuda.current_device())
+
+        global _MATMUL_INPUT
+        matmul_input = _MATMUL_INPUT
 
         # Raw attention scores. [b * np, sq, sk]
         matmul_result = torch.baddbmm(
-            matmul_result,
+            matmul_input,
             query_layer.transpose(0, 1),   # [b * np, sq, hn]
             key_layer.transpose(0, 1).transpose(1, 2),  # [b * np, hn, sk]
             beta=0.0, alpha=(1.0/self.norm_factor))
@@ -838,6 +853,7 @@ class ParallelTransformer(MegatronModule):
                     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':
             # Checkpoint the input activation of only a set number of individual
             # Transformer layers and skip the rest.
@@ -869,25 +885,12 @@ class ParallelTransformer(MegatronModule):
     def forward(self, hidden_states, attention_mask,
                 encoder_output=None, enc_dec_attn_mask=None,
                 inference_params=None):
-
         # Checks.
         if inference_params:
             assert self.activations_checkpoint_method is None, \
                 'inference does not work with activation checkpointing'
 
-        if self.pre_process:
-            # Data format change to avoid explicit tranposes : [b s h] --> [s b h].
-            # If the input flag for fp32 residual connection is set, convert for float.
-            if self.fp32_residual_connection:
-                hidden_states = hidden_states.transpose(0, 1).contiguous().float()
-            # Otherwise, leave it as is.
-            else:
-                hidden_states = hidden_states.transpose(0, 1).contiguous()
-
-            if self.model_parallel_memory_opt:
-                hidden_states = mpu.scatter_to_sequence_parallel_region(hidden_states)
-
-        else:
+        if not self.pre_process:
             # See set_input_tensor()
             hidden_states = self.input_tensor
 
@@ -908,17 +911,10 @@ class ParallelTransformer(MegatronModule):
         #   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,
+            requires_grad=True,
+            keep_graph=True,
         )
 
-        # Transpose encoder output.
-        if encoder_output is not None and \
-                not self.model_parallel_memory_opt:
-            encoder_output = encoder_output.transpose(0, 1).contiguous()
-            if self.model_parallel_memory_opt:
-                encoder_output = mpu.scatter_to_sequence_parallel_region(encoder_output)
-
         if self.model_parallel_memory_opt:
             with mpu.get_cuda_rng_tracker().fork():
                 # Forward pass.
@@ -928,6 +924,7 @@ class ParallelTransformer(MegatronModule):
                                                                encoder_output,
                                                                enc_dec_attn_mask)
                 else:
+                    total = 0
                     for index in range(self.num_layers):
                         layer = self._get_layer(index)
                         hidden_states = layer(
@@ -936,6 +933,7 @@ class ParallelTransformer(MegatronModule):
                             encoder_output=encoder_output,
                             enc_dec_attn_mask=enc_dec_attn_mask,
                             inference_params=inference_params)
+                         
         else:
             # Forward pass.
             if self.activations_checkpoint_method is not None:
@@ -955,20 +953,6 @@ class ParallelTransformer(MegatronModule):
 
         # Final layer norm.
         if self.post_process:
-            # Reverting data format change [s b h] --> [b s h].
             hidden_states = self.final_layernorm(hidden_states)
 
-            if self.layer_type == LayerType.encoder and \
-                    self.model_type == ModelType.encoder_and_decoder and \
-                    self.model_parallel_memory_opt:
-                output = hidden_states
-            else:
-
-                if self.model_parallel_memory_opt:
-                    hidden_states = mpu.gather_from_sequence_parallel_region(hidden_states)
-
-                output = hidden_states.transpose(0, 1).contiguous()
-        else:
-            output = hidden_states
-
-        return output
+        return hidden_states

megatron/mpu/layers.py

@@ -41,11 +41,12 @@ from .utils import split_tensor_along_last_dim
 from .utils import VocabUtility
 from megatron import get_args
 
-
 _MODEL_PARALLEL_ATTRIBUTE_DEFAULTS = {'tensor_model_parallel': False,
                                       'partition_dim': -1,
                                       'partition_stride': 1}
 
+_TOTAL_INPUT = None
+_SUB_GRAD_INPUT = None
 
 def param_is_not_tensor_parallel_duplicate(param):
     return (hasattr(param, 'tensor_model_parallel') and
@@ -221,9 +222,11 @@ class LinearWithGradAccumulationAndAsyncCommunication(torch.autograd.Function):
             dim_size = list(input.size())
             dim_size[0] = dim_size[0] * world_size
 
-            total_input = torch.empty(dim_size, dtype=input.dtype,
-                                      device=torch.cuda.current_device(),
-                                      requires_grad=False)
+            #total_input = torch.empty(dim_size, dtype=input.dtype,
+            #                          device=torch.cuda.current_device(),
+            #                          requires_grad=False)
+            global _TOTAL_INPUT
+            total_input = _TOTAL_INPUT
             torch.distributed._all_gather_base(total_input, input,
                                                group=get_tensor_model_parallel_group())
         
@@ -246,9 +249,12 @@ class LinearWithGradAccumulationAndAsyncCommunication(torch.autograd.Function):
             dim_size = list(input.size())
             dim_size[0] = dim_size[0] * world_size
 
-            total_input = torch.empty(dim_size, dtype=input.dtype,
-                                      device=torch.cuda.current_device(),
-                                      requires_grad=False)
+            #total_input = torch.empty(dim_size, dtype=input.dtype,
+            #                          device=torch.cuda.current_device(),
+            #                          requires_grad=False)
+            global _TOTAL_INPUT
+            total_input = _TOTAL_INPUT
+
             handle = torch.distributed._all_gather_base(total_input, input,
                                            group=get_tensor_model_parallel_group(), async_op=True)
             # Delay the start of intput gradient computation shortly (3us) to have
@@ -390,6 +396,11 @@ class ColumnParallelLinear(torch.nn.Module):
         assert not self.async_tensor_model_parallel_allreduce or \
             not self.model_parallel_memory_opt
         self.gradient_accumulation_fusion = args.gradient_accumulation_fusion
+        global _TOTAL_INPUT
+        if _TOTAL_INPUT is None:
+            _TOTAL_INPUT = torch.empty((args.seq_length, args.micro_batch_size, args.hidden_size), dtype=torch.bfloat16,
+                                       device=torch.cuda.current_device(),
+                                       requires_grad=False)
 
 
     def forward(self, input_):

megatron/optimizer/optimizer.py

@@ -265,6 +265,13 @@ class Float16OptimizerWithFloat16Params(MegatronOptimizer):
                             self.optimizer.state[main_param] \
                                 = self.optimizer.state.pop(param)
                     
+                        #state = self.optimizer.state[main_param]
+                        #if len(state) == 0:
+                        #    # Exponential moving average of gradient values
+                        #    state['exp_avg'] = torch.zeros_like(main_param.data)
+                        #    # Exponential moving average of squared gradient values
+                        #    state['exp_avg_sq'] = torch.zeros_like(main_param.data)
+
                     # fp32 params.
                     elif param.type() == 'torch.cuda.FloatTensor':
                         fp32_params_this_group.append(param)
@@ -284,7 +291,7 @@ class Float16OptimizerWithFloat16Params(MegatronOptimizer):
 
         # Leverage state_dict() and load_state_dict() to
         # recast preexisting per-param state tensors
-        self.optimizer.load_state_dict(self.optimizer.state_dict())
+        # self.optimizer.load_state_dict(self.optimizer.state_dict())
         
 
     def zero_grad(self, set_to_none=True):

megatron/schedules.py

@@ -517,8 +517,15 @@ def get_tensor_shapes(rank, model_type):
 
     if args.model_parallel_memory_opt:
         seq_length = args.seq_length // mpu.get_tensor_model_parallel_world_size()
+    else:
+        seq_length = args.seq_length
+
     if model_type == ModelType.encoder_and_decoder:
+        if args.model_parallel_memory_opt:
             decoder_seq_length = args.decoder_seq_length // mpu.get_tensor_model_parallel_world_size()
+        else:
+            decoder_seq_length = args.decoder_seq_length
+
         if mpu.is_pipeline_stage_before_split(rank):
             tensor_shapes.append((seq_length, args.micro_batch_size, args.hidden_size))
         else:
@@ -526,21 +533,6 @@ def get_tensor_shapes(rank, model_type):
             tensor_shapes.append((seq_length, args.micro_batch_size, args.hidden_size))
     else:
         tensor_shapes.append((seq_length, args.micro_batch_size, args.hidden_size))
-
-        return tensor_shapes
-
-    if model_type == ModelType.encoder_and_decoder:
-        if mpu.is_pipeline_stage_before_split(rank):
-            # If next rank is after split, then need transpose for encoder_hidden_state.
-            if mpu.is_pipeline_stage_before_split(rank+1):
-                tensor_shapes.append((args.seq_length, args.micro_batch_size, args.hidden_size))
-            else:
-                tensor_shapes.append((args.micro_batch_size, args.seq_length, args.hidden_size))
-        else:
-            tensor_shapes.append((args.decoder_seq_length, args.micro_batch_size, args.hidden_size))
-            tensor_shapes.append((args.micro_batch_size, args.seq_length, args.hidden_size))
-    else:
-        tensor_shapes.append((args.seq_length, args.micro_batch_size, args.hidden_size))
     return tensor_shapes
 
 

megatron/training.py

@@ -432,7 +432,8 @@ def train_step(forward_step_func, data_iterator,
                     grad = param.main_grad if args.DDP_impl == 'local' else param.grad
                     grads.append(grad.data)
         coalesced = _flatten_dense_tensors(grads)
-        coalesced /= mpu.get_tensor_model_parallel_world_size()
+        #TODO VIJAY
+        #coalesced /= mpu.get_tensor_model_parallel_world_size()
         torch.distributed.all_reduce(
             coalesced, group=mpu.get_tensor_model_parallel_group())
         for buf, synced in zip(grads, _unflatten_dense_tensors(

pretrain_gpt.py

@@ -59,7 +59,7 @@ def get_batch(data_iterator):
 
     # Unpack.
     tokens_ = data_b['text'].long()
-    labels = tokens_[:, 1:].contiguous()
+    labels = tokens_[:, 1:].transpose(0,1).contiguous()
     tokens = tokens_[:, :-1].contiguous()
 
     # Get the masks and postition ids.