basic chunk

chunk_codegen.py

@@ -18,16 +18,61 @@ else:
     __all__ = ['python_code_with_activation_checkpoint']
 
 
-def _gen_loop_start(to_keep, chunk_size=2):
-    context = "chunk_result = []; chunk_size = %d\nfor gen_loop_idx in range(0, %s.shape[0], chunk_size):\n" % (chunk_size, to_keep[0])
-    context += "    chunk_tensor = " + to_keep + "[gen_loop_idx:gen_loop_idx + chunk_size, :]\n"
+def _gen_chunk_slice_dim(chunk_dim, chunk_idx_name, shape):
+    new_shape = "["
+    for idx, i in enumerate(shape):
+        if idx == chunk_dim:
+            new_shape += "%s:%s + chunk_size" % (chunk_idx_name, chunk_idx_name)
+        else:
+            new_shape += ":"
+        new_shape += ", "
+    new_shape = new_shape[:-2] + "]"
+    return new_shape
+
+
+def _get_first_non_single_dim(shape):
+    for idx, i in enumerate(shape):
+        if i == 1:
+            continue
+        else:
+            return idx
+    raise RuntimeError("can not get first non single dim for shape", shape)
+
+
+def _gen_loop_start(chunk_input_meta, chunk_output, chunk_size=2):
+    if len(chunk_input_meta) == 1:
+        node = chunk_input_meta[0]
+        node_shape = node.meta['tensor_meta'].shape
+        chunk_dim = _get_first_non_single_dim(node_shape)
+        chunk_slice = _gen_chunk_slice_dim(chunk_dim, "gen_chunk_idx", node_shape)
+        out_shape = str(list(chunk_output.meta['tensor_meta'].shape))
+        
+        context = "chunk_result = torch.empty(%s, dtype=%s.dtype, device=%s.device); chunk_size = %d\nfor gen_chunk_idx in range" % (
+            out_shape, node.name, node.name, chunk_size)
+        context += "(0, %s.shape[%d], chunk_size):\n" % (node.name, chunk_dim)
+        context += "    chunk_tensor = %s%s\n" % (node.name, chunk_slice)
+    else:
+        raise NotImplementedError("input with size %d not implemented" % len(chunk_input_meta))
     return context
 
 
-def _gen_loop_end(final_name, to_keep):
-    context = "    chunk_result.append(" + final_name + ")\n"
-    context += "chunk_result = torch.cat(chunk_result, dim=0);  " + to_keep[0] + " = None\n"
-    context += final_name + " = chunk_result; chunk_result = None\n"
+def _gen_loop_end(chunk_outputs, chunk_inputs, node_list):
+    chunk_inputs_name = chunk_inputs[0].name
+    chunk_outputs_name = chunk_outputs.name
+    chunk_outputs_idx = _find_idx_by_name(chunk_outputs_name, node_list)
+    chunk_output_shape = chunk_outputs.meta['tensor_meta'].shape
+    chunk_dim = _get_first_non_single_dim(chunk_output_shape)
+    chunk_slice = _gen_chunk_slice_dim(chunk_dim, "gen_chunk_idx", chunk_output_shape)
+    context = "    chunk_result%s = %s\n" % (chunk_slice, chunk_outputs_name)
+
+    context += chunk_outputs_name + " = chunk_result;  chunk_result = None;  chunk_size = None"
+    
+    # determine if its the last use for chunk input
+    users_name = list(chunk_inputs[0].users.keys())
+    if all([_find_idx_by_name(user.name, node_list) <= chunk_outputs_idx for user in users_name]):
+        context += ";  %s = None" % chunk_inputs_name
+
+    context += "\n"
     return context
 
 
@@ -44,7 +89,7 @@ def _find_input_and_output_nodes(nodes: List[Node]):
         for input_node in node._input_nodes.keys():
             node_repr = repr(input_node)
             if input_node not in nodes and node_repr not in input_nodes:
-                input_nodes.append(node_repr)
+                input_nodes.append(input_node)
 
     # if a node has a user node which is not in the node list
     # we treat that user node as the node receiving the current node output
@@ -52,11 +97,18 @@ def _find_input_and_output_nodes(nodes: List[Node]):
         for output_node in node.users.keys():
             node_repr = repr(node)
             if output_node not in nodes and node_repr not in output_nodes:
-                output_nodes.append(node_repr)
+                output_nodes.append(output_node)
 
     return input_nodes, output_nodes
 
 
+def _find_idx_by_name(name, nodes_list):
+    for idx, node in enumerate(nodes_list):
+        if node.name == name:
+            return idx
+    raise RuntimeError("name %s not found in node list" % name)
+        
+
 def _find_offload_regions(nodes: List[Node]):
     """This function is to find the offload regions
     In pofo algorithm, during annotation, we will annotate the offload region with the 
@@ -290,7 +342,7 @@ def emit_ckpt_func(body,
             body.append(usage)
 
 
-def emit_code_with_chunk(body, ckpt_func, nodes, emit_node_func, delete_unused_value_func):
+def emit_code_with_chunk(body, ckpt_func, nodes, emit_node_func, delete_unused_value_func, meta_nodes):
     """Emit code with nested activation checkpoint
     When we detect some of the node.activation_checkpoint is a List, we will use
     this function to emit the activation checkpoint codes.
@@ -304,7 +356,7 @@ def emit_code_with_chunk(body, ckpt_func, nodes, emit_node_func, delete_unused_v
     """
 
     # find the offload regions
-    chunk_regions = [(1, 4)]
+    chunk_regions = [(2, 5)]
     chunk_starts = [item[0] for item in chunk_regions]
     chunk_ends = [item[1] for item in chunk_regions]
     chunk_inputs = []
@@ -319,46 +371,44 @@ def emit_code_with_chunk(body, ckpt_func, nodes, emit_node_func, delete_unused_v
         inputs, outputs = _find_input_and_output_nodes(offload_node_list)
         chunk_inputs.append(inputs)
         chunk_outputs.append(outputs)
+    chunk_inputs_idx = [[_find_idx_by_name(j.name, node_list) for j in i] for i in chunk_inputs]
+    chunk_outputs_idx = [[_find_idx_by_name(j.name, node_list) for j in i] for i in chunk_outputs]
+    chunk_inputs_names = []
+    for i in chunk_inputs:
+        for j in i:
+            chunk_inputs_names.append(j.name)
     
     # this flag is to prevent repeated insert of save tensors
     # hooks definition in ckpt_func
     node_idx = 0
-    chunk_var = []
+    region_idx = 0
     while node_idx < len(node_list):
-        # break if we finish the processing all the nodes
-        if node_idx >= len(node_list):
-            break
-
-        # process node in forward function
-        else:
         node = node_list[node_idx]
 
         if node_idx in chunk_starts:
             within_chunk_region = True
                 
-                # save chunk input var, dont delete it
-                chunk_var.append(node.args[0].name)
-                
             # add for loop
-                body.append(_gen_loop_start(chunk_var[0]))
+            chunk_input_meta = [meta_nodes[i] for i in chunk_inputs_idx[region_idx]]
+            body.append(_gen_loop_start(chunk_input_meta, node_list[chunk_ends[region_idx]]))
 
         if within_chunk_region:
             emit_node_func(node, body)
             # replace input var with chunk var
             if node_idx in chunk_starts:
-                    body[-1] = body[-1].replace("("+ chunk_var[0] +")", '(chunk_tensor)')
+                body[-1] = body[-1].replace("("+ chunk_inputs[region_idx][0].name +")", '(chunk_tensor)')
             body[-1] = '    ' + body[-1]
-                delete_unused_value_func(node, body, chunk_var)
+            delete_unused_value_func(node, body, chunk_inputs_names)
 
         else:
             emit_node_func(node, body)
             if node_idx not in chunk_inputs:
-                    delete_unused_value_func(node, body, chunk_var)
+                delete_unused_value_func(node, body, chunk_inputs_names)
 
         if node_idx in chunk_ends:
-                body.append(_gen_loop_end(node.name, chunk_var))
-                chunk_var = []
+            body.append(_gen_loop_end(node, chunk_inputs[region_idx], node_list))
             within_chunk_region = False
+            region_idx += 1
 
         node_idx += 1
 
@@ -562,7 +612,7 @@ if CODEGEN_AVAILABLE:
 
             # if any node has a list of labels for activation_checkpoint, we
             # will use nested type of activation checkpoint codegen
-            emit_code_with_chunk(body, ckpt_func, nodes, emit_node, delete_unused_values)
+            emit_code_with_chunk(body, ckpt_func, nodes, emit_node, delete_unused_values, self.meta_node)
 
             if len(body) == 0:
                 # If the Graph has no non-placeholder nodes, no lines for the body

chunk_codegen_run.py

@@ -70,7 +70,7 @@ def _run_offload_codegen(rank):
     #         setattr(node, "activation_offload", [0, True, False])
 
     codegen = ChunkCodeGen(gm_prop)
-    # graph.set_codegen(codegen)
+    graph.set_codegen(codegen)
     gm = ColoGraphModule(model, graph)
     gm.recompile()