[embeddings] add already_split_along_rank flag for tablewise mode (#1584

)

colossalai/nn/parallel/layers/cache_embedding/parallel_freq_aware_embedding_tablewise.py

@@ -9,6 +9,7 @@
 from colossalai.nn._ops._utils import dual_all_to_all_tablewise
 
 from typing import List
+import time
 
 
 class ParallelFreqAwareEmbeddingBagTablewise(FreqAwareEmbeddingBag):
@@ -79,8 +80,43 @@ def __init__(self,
         for rank in self.rank_of_tables:
             self.embedding_dim_per_rank[rank] += embedding_dim
 
-    def forward(self, indices: torch.Tensor, offsets: torch.Tensor = None, per_sample_weights=None, shape_hook=None):
-        batch_size = (offsets.shape[0]) // self.global_tables_num
+    def forward(self,
+                indices: torch.Tensor,
+                offsets: torch.Tensor = None,
+                per_sample_weights=None,
+                shape_hook=None,
+                already_split_along_rank=True):
+        if not already_split_along_rank:
+            # not recommanded. it takes time.
+            batch_size = (offsets.shape[0]) // self.global_tables_num
+            local_indices, local_offsets, local_per_sample_weights = self.split_along_rank(
+                batch_size, indices, offsets, per_sample_weights)
+        else:
+            # recommanded.
+            batch_size = (offsets.shape[0]) // len(self.assigned_table_list)
+            local_indices, local_offsets, local_per_sample_weights = indices, offsets, per_sample_weights
+        with torch.no_grad():
+            reorder_ids = self.cache_weight_mgr.prepare_ids(local_indices)
+        local_output = F.embedding_bag(reorder_ids.cuda(), self.cache_weight_mgr.cuda_cached_weight, local_offsets,
+                                       self.max_norm, self.norm_type, self.scale_grad_by_freq, self.mode, self.sparse,
+                                       local_per_sample_weights, self.include_last_offset, self.padding_idx)
+        local_output = torch.cat(local_output.split(batch_size), 1)
+        remains = batch_size % self.world_size
+        scatter_strides = [batch_size // self.world_size + int(i < remains) for i in range(self.world_size)]
+        output_full = dual_all_to_all_tablewise(local_output, self.pg, scatter_strides, self.embedding_dim_per_rank)
+        if shape_hook is not None:
+            output_full = shape_hook(output_full)
+        return output_full
+
+    def split_along_rank(self,
+                         batch_size,
+                         indices: torch.Tensor,
+                         offsets: torch.Tensor = None,
+                         per_sample_weights=None):
+        '''
+        if input indices and offsets haven't been splitted along assigned rank, this function will do it.
+        it takes time. please consider splitting data during batch loading.
+        '''
         local_indices_list: List(torch.Tensor) = []
         local_offsets_list: List(torch.Tensor) = []
         if per_sample_weights != None:
@@ -145,20 +181,7 @@ def forward(self, indices: torch.Tensor, offsets: torch.Tensor = None, per_sampl
         local_per_sample_weights = None
         if per_sample_weights != None:
             local_per_sample_weights = torch.cat(local_per_sample_weights_list, 0)
-        with torch.no_grad():
-            reorder_ids = self.cache_weight_mgr.prepare_ids(local_indices)
-
-        local_output = F.embedding_bag(reorder_ids.cuda(), self.cache_weight_mgr.cuda_cached_weight, local_offsets,
-                                       self.max_norm, self.norm_type, self.scale_grad_by_freq, self.mode, self.sparse,
-                                       local_per_sample_weights, self.include_last_offset, self.padding_idx)
-        local_output = torch.cat(local_output.split(batch_size), 1)
-
-        remains = batch_size % self.world_size
-        scatter_strides = [batch_size // self.world_size + int(i < remains) for i in range(self.world_size)]
-        output_full = dual_all_to_all_tablewise(local_output, self.pg, scatter_strides, self.embedding_dim_per_rank)
-        if shape_hook is not None:
-            output_full = shape_hook(output_full)
-        return output_full
+        return local_indices, local_offsets, local_per_sample_weights
 
     def print_comm_stats_(self):
         self.cache_weight_mgr.print_comm_stats()

tests/test_layers/test_cache_embedding.py

@@ -253,7 +253,8 @@ def run_parallel_freq_aware_embed_tablewise(rank, world_size):
     in KJT format
     '''
     res = model(torch.tensor([1, 2, 3, 1, 5, 6, 7, 9, 6, 8, 13, 15, 11], device=device),
-                torch.tensor([0, 3, 3, 5, 7, 8, 10, 10, 12, 13], device=device))
+                torch.tensor([0, 3, 3, 5, 7, 8, 10, 10, 12, 13], device=device),
+                already_split_along_rank=False)
     optimizer = torch.optim.SGD(model.parameters(), lr=1e-2)
     rand_grad = torch.rand(3, 5 * 3, dtype=res.dtype, device=res.device)
     if rank == 0: