DualPipeV Fw-Bw Overlapping pass with User Annotations

stack-info: PR: #261, branch: sanketpurandare/stack/2

Author: sanketpurandare

autoparallel/_passes/graph_multiplex.py

@@ -4,13 +4,44 @@
 # LICENSE file in the root directory of this source tree.
 
 import copy
+from itertools import dropwhile
 
 import torch
 import torch.fx as fx
+from torch._inductor.fx_passes.bucketing import is_wait_tensor
+from torch._logging import trace_structured
+
+
+def _add_compute_annotations(gm: fx.GraphModule, tag: str):
+    """Add compute_region annotations to nodes without custom metadata."""
+    for n in gm.graph.nodes:
+        if n.op == "placeholder":
+            continue
+        if n.meta.get("custom", None) is None:
+            n.meta["custom"] = {"compute_region": tag}
+        else:
+            assert "comm_region" in n.meta["custom"]
+            val = n.meta["custom"]["comm_region"]
+            n.meta["custom"]["comm_region"] = tag + " " + val
+
+
+def _move_wait_tensors_to_compute_region(gm: fx.GraphModule, tag: str):
+    """Move wait_tensor nodes from comm_region to compute_region of their users."""
+    for n in gm.graph.nodes:
+        if n.op == "placeholder":
+            continue
+        if "comm_region" in n.meta["custom"] and is_wait_tensor(n):
+            assert len(n.users) >= 1, "wait tensor must have at least one user"
+            user: fx.Node = next(iter(n.users))
+            if "compute_region" in user.meta["custom"]:
+                n.meta["custom"].pop("comm_region")
+                n.meta["custom"].update({"compute_region": tag + " " + "wait"})
+                if n.next is not user:
+                    user.prepend(n)
 
 
 def multiplex_fw_bw_graph(
-    fw_gm: fx.GraphModule, bw_gm: fx.GraphModule
+    fw_gm: fx.GraphModule, bw_gm: fx.GraphModule, overlap_with_annotations: bool = True
 ) -> fx.GraphModule:
     """
     Multiplexes forward and backward graphs into a single unified graph module.
@@ -32,67 +63,116 @@ def multiplex_fw_bw_graph(
     Note:
         The function preserves node metadata during the merging process.
     """
-    # Mapping to track correspondence between backward graph nodes and new nodes
+    if overlap_with_annotations:
+        _add_compute_annotations(fw_gm, "forward")
+        _add_compute_annotations(bw_gm, "backward")
+        _move_wait_tensors_to_compute_region(fw_gm, "forward")
+        _move_wait_tensors_to_compute_region(bw_gm, "backward")
+
+    # Mapping to track correspondence between forward graph nodes and new nodes
     old_node_to_new_node: dict[torch.fx.Node, torch.fx.Node] = {}
 
-    # Start with a deep copy of the forward graph as the base
-    multiplexed_gm = copy.deepcopy(fw_gm)
+    # Start with a deep copy of the backward graph as the base
+    multiplexed_gm = copy.deepcopy(bw_gm)
 
-    # Collect all placeholder nodes from the backward graph
+    # Collect all placeholder nodes from all the graphs
     bw_placeholders = bw_gm.graph.find_nodes(op="placeholder")
     fw_placeholders = fw_gm.graph.find_nodes(op="placeholder")
+    insert_point = multiplexed_gm.graph.find_nodes(op="placeholder")[-1]
 
-    # Insert backward placeholders at the beginning of the multiplexed graph
-    # Reversed order ensures correct execution sequence
-    with multiplexed_gm.graph.inserting_before():
-        for n in reversed(bw_placeholders):
+    # Insert forward placeholders after the backward placeholders of the multiplexed graph
+    for n in fw_placeholders:
+        with multiplexed_gm.graph.inserting_after(insert_point):
             new_placeholder = multiplexed_gm.graph.placeholder(n.name)
-            new_placeholder.meta = n.meta
+            new_placeholder.meta = copy.copy(n.meta)
             new_placeholder.target = new_placeholder.name
             old_node_to_new_node[n] = new_placeholder
+            insert_point = new_placeholder
 
-    # Find the last placeholder and the output node in the multiplexed graph
-    multiplxed_gm_placeholders = multiplexed_gm.graph.find_nodes(op="placeholder")
-    assert len(multiplxed_gm_placeholders) == (
-        len(fw_placeholders) + len(bw_placeholders)
+    multiplexed_gm_placeholders = multiplexed_gm.graph.find_nodes(op="placeholder")
+    assert len(multiplexed_gm_placeholders) == len(fw_placeholders) + len(
+        bw_placeholders
     )
-    insert_point = multiplxed_gm_placeholders[-1]
-
-    # Copy all computation nodes from backward graph into multiplexed graph
-    fw_outputs = fw_gm.graph.find_nodes(op="output")
-    bw_outputs = bw_gm.graph.find_nodes(op="output")
-    assert len(bw_outputs) == 1 and len(fw_outputs) == 1
-    bw_graph_op_node = bw_outputs[0]
-    for n in bw_gm.graph.nodes:
-        if n.op == "placeholder":
-            continue
-        if n.op == "output":
-            continue
-        with multiplexed_gm.graph.inserting_after(insert_point):
+    fw_nodes_iter = iter(fw_gm.graph.nodes)
+    fw_nodes_iter = dropwhile(lambda n: n.op == "placeholder", fw_nodes_iter)
+    # Initialize the forward node to be the first non-placeholder node
+    fn = next(fw_nodes_iter)
+    if overlap_with_annotations:
+        # Interleave forward and backward nodes to create overlap pattern:
+        # bw_compute (if any) -> bw_comm -> fw_compute (if any) -> fw_comm -> [repeat]
+        # This allows bw_comm to overlap with fw_compute, and fw_comm to overlap with bw_compute
+        bw_in_comm = False
+        for bn in multiplexed_gm.graph.nodes:
+            if bn.op == "placeholder" or bn.op == "output":
+                continue
+            # Track when we enter a backward comm region
+            if "comm_region" in bn.meta["custom"] and not bw_in_comm:
+                bw_in_comm = True
+            # When we transition from bw_comm to bw_compute, insert forward nodes
+            elif "compute_region" in bn.meta["custom"] and bw_in_comm:
+                bw_in_comm = False
+                fw_in_comm = False
+                insert_point = bn
+                # Insert forward nodes before this bw_compute node
+                # Note: We cannot reorder nodes within a graph, only their relative order between graphs
+                while fn.op != "output":
+                    if "comm_region" in fn.meta["custom"] and not fw_in_comm:
+                        fw_in_comm = True
+                    elif "compute_region" in fn.meta["custom"] and fw_in_comm:
+                        # Stop when we reach the next fw_compute after fw_comm
+                        # This ensures we insert one fw_compute + fw_comm cycle per bw_comm -> bw_compute transition
+                        # If fw starts with comm (no compute before it), we still insert it to overlap with future bw_compute
+                        fw_in_comm = False
+                        break
+                    with multiplexed_gm.graph.inserting_before(insert_point):
+                        # Copy node and remap its arguments using the node mapping
+                        new_node = multiplexed_gm.graph.node_copy(
+                            fn, lambda x: old_node_to_new_node[x]
+                        )
+                        new_node.meta = copy.copy(fn.meta)
+                        old_node_to_new_node[fn] = new_node
+                    fn = next(fw_nodes_iter)
+    # Insert any remaining forward nodes at the end
+    # If overlap_with_annotations is False, this concatenates all fw nodes after bw nodes
+    insert_point = multiplexed_gm.graph.find_nodes(op="output")[-1]
+    while fn.op != "output":
+        with multiplexed_gm.graph.inserting_before(insert_point):
             # Copy node and remap its arguments using the node mapping
             new_node = multiplexed_gm.graph.node_copy(
-                n, lambda x: old_node_to_new_node[x]
+                fn, lambda x: old_node_to_new_node[x]
             )
-            new_node.meta = n.meta
-            old_node_to_new_node[n] = new_node
-            insert_point = new_node
+            new_node.meta = copy.copy(fn.meta)
+            old_node_to_new_node[fn] = new_node
+        fn = next(fw_nodes_iter)
 
-    # Collect output arguments from backward graph, remapping to new nodes
-    bw_op_node_args = [
+    # Collect output arguments from forward graph, remapping to new nodes
+    fw_outputs = fw_gm.graph.find_nodes(op="output")
+    multiplexed_graph_outputs = multiplexed_gm.graph.find_nodes(op="output")
+    assert len(multiplexed_graph_outputs) == 1 and len(fw_outputs) == 1
+    fw_graph_op_node = fw_outputs[0]
+    fw_op_node_args = [
         old_node_to_new_node[n] if n is not None else None
-        for n in bw_graph_op_node.args[0]
+        for n in fw_graph_op_node.args[0]
     ]
 
-    # Collect output arguments from multiplexed graph (will contain only fwd_outs)
-    multiplexed_graph_outputs = multiplexed_gm.graph.find_nodes(op="output")
-    assert len(multiplexed_graph_outputs) == 1
+    # Collect output arguments from multiplexed graph (will contain only bwd_outs)
     multiplexed_graph_op_node = multiplexed_graph_outputs[0]
-    fw_op_node_args = list(multiplexed_graph_op_node.args[0])
+    bw_op_node_args = list(multiplexed_graph_op_node.args[0])
 
     # Update output node args to prepend backward outputs before forward outputs
     multiplexed_graph_op_node.args = (tuple(bw_op_node_args + fw_op_node_args),)
 
     multiplexed_gm.graph.eliminate_dead_code()
     multiplexed_gm.graph.lint()
     multiplexed_gm.recompile()
+    trace_structured(
+        "artifact",
+        metadata_fn=lambda: {
+            "name": "autoparallel_multiplexed_graph",
+            "encoding": "string",
+        },
+        payload_fn=lambda: multiplexed_gm.print_readable(
+            print_output=False, include_stride=True, include_device=True
+        ),
+    )
     return multiplexed_gm

autoparallel/_testing/models/dsv3.py

@@ -8,6 +8,7 @@
 from typing import Callable, ClassVar, Literal, Optional, Tuple, Union
 
 import torch
+import torch.fx.traceback as fx_traceback
 import torch.nn.functional as F
 import triton
 import triton.language as tl
@@ -631,61 +632,63 @@ def forward(
 
 
 def _token_dispatch(routed_input, num_tokens_per_expert, axis_name):
-    # annotate module input placements/sharding with input_layouts
-    # ep_size = device_mesh.shape[0]
-    ep_size = axis_size(axis_name)
-
-    # generate the input splits and output splits for all-to-all
-    with torch.no_grad():
-        num_tokens_per_expert_group = all_to_all(
-            num_tokens_per_expert,
-            None,
-            None,
+    with fx_traceback.annotate({"comm_region": "token_dispatch"}):
+        # annotate module input placements/sharding with input_layouts
+        # ep_size = device_mesh.shape[0]
+        ep_size = axis_size(axis_name)
+
+        # generate the input splits and output splits for all-to-all
+        with torch.no_grad():
+            num_tokens_per_expert_group = all_to_all(
+                num_tokens_per_expert,
+                None,
+                None,
+                axis_name,
+            )
+            input_splits = (
+                num_tokens_per_expert.view(ep_size, -1)
+                .sum(dim=1)
+                .to(torch.device("cpu"), non_blocking=True)
+            )
+            # NOTE: this would incur a device-to-host sync
+            output_splits = (
+                num_tokens_per_expert_group.view(ep_size, -1)
+                .sum(dim=1)
+                .to(torch.device("cpu"), non_blocking=False)
+            )
+            input_splits = input_splits.tolist()
+            output_splits = output_splits.tolist()
+
+        # perform all-to-all
+        routed_input = all_to_all(
+            routed_input,
+            output_splits,
+            input_splits,
             axis_name,
         )
-        input_splits = (
-            num_tokens_per_expert.view(ep_size, -1)
-            .sum(dim=1)
-            .to(torch.device("cpu"), non_blocking=True)
-        )
-        # NOTE: this would incur a device-to-host sync
-        output_splits = (
-            num_tokens_per_expert_group.view(ep_size, -1)
-            .sum(dim=1)
-            .to(torch.device("cpu"), non_blocking=False)
-        )
-        input_splits = input_splits.tolist()
-        output_splits = output_splits.tolist()
-
-    # perform all-to-all
-    routed_input = all_to_all(
-        routed_input,
-        output_splits,
-        input_splits,
-        axis_name,
-    )
 
-    # NOTE: After this all-to-all, the routed input is put on proper EP rank.
-    # However, the num_tokens_per_expert_group is not of the final target format
-    # [#tokens for local expert 0, #tokens for local expert 1, ...]
-    # Rather, it is of the format
-    # [#tokens for local expert 0 from EP rank 0, #tokens for local expert 1 from EP rank 0, ...,
-    #  #tokens for local expert 0 from EP rank 1, #tokens for local expert 1 from EP rank 1, ...]
-    # We need to perform another shuffle to get the correct format -- this is done via the function
-    # generate_permute_indices in moe.py, which also does padding to make sure the number of tokens
-    # each expert gets locally is a multiple of ALIGN_SIZE_M.
+        # NOTE: After this all-to-all, the routed input is put on proper EP rank.
+        # However, the num_tokens_per_expert_group is not of the final target format
+        # [#tokens for local expert 0, #tokens for local expert 1, ...]
+        # Rather, it is of the format
+        # [#tokens for local expert 0 from EP rank 0, #tokens for local expert 1 from EP rank 0, ...,
+        #  #tokens for local expert 0 from EP rank 1, #tokens for local expert 1 from EP rank 1, ...]
+        # We need to perform another shuffle to get the correct format -- this is done via the function
+        # generate_permute_indices in moe.py, which also does padding to make sure the number of tokens
+        # each expert gets locally is a multiple of ALIGN_SIZE_M.
 
-    return routed_input, num_tokens_per_expert_group, input_splits, output_splits
+        return routed_input, num_tokens_per_expert_group, input_splits, output_splits
 
 
 def _token_combine(routed_output, input_splits, output_splits, axis_name):
-    routed_output = all_to_all(
-        routed_output,
-        input_splits,
-        output_splits,
-        axis_name,
-    )
-    return routed_output
+    with fx_traceback.annotate({"comm_region": "token_combine"}):
+        routed_output = all_to_all(
+            routed_output,
+            input_splits,
+            output_splits,
+            axis_name,
+        )
+        return routed_output
 
 
 # @torch.library.custom_op("autoparallel::local_mapped_region", mutates_args=())

autoparallel/graph_pp_runner.py

@@ -70,7 +70,9 @@ def get_multiplexed_graph_callables(
         for fw_stage_idx, fw_stage_graph_callables in stage_graphs.items():
             if bw_stage_idx != fw_stage_idx:
                 fw_bw_module = multiplex_fw_bw_graph(
-                    fw_stage_graph_callables.fw, bw_stage_graph_callables.full_bw
+                    fw_stage_graph_callables.fw,
+                    bw_stage_graph_callables.full_bw,
+                    overlap_with_annotations=True,
                 )
                 multiplexed_graph_callables[(fw_stage_idx, bw_stage_idx)] = fw_bw_module
     return multiplexed_graph_callables

examples/example_pp_graph_passes.py

@@ -183,9 +183,8 @@ def _run_graph_test(
     """Execute forward and backward passes with specified graph options."""
     if use_multiplexed_graph:
         multiplexed_fw_bw_module = multiplex_fw_bw_graph(
-            graph_modules.fw, graph_modules.full_bw
+            graph_modules.fw, graph_modules.full_bw, overlap_with_annotations=True
         )
-
     with (
         FakeTensorMode(
             allow_non_fake_inputs=True,