[PyTorch] Add option to pass kwargs to CUDA graph module (#945)

* Add option to pass kwargs to CUDA graph module
Signed-off-by: Tim Moon <tmoon@nvidia.com>

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* Debug unit tests
Signed-off-by: Tim Moon <tmoon@nvidia.com>

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* Tweak comments
Signed-off-by: Tim Moon <tmoon@nvidia.com>

---------
Signed-off-by: Tim Moon <tmoon@nvidia.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Kirthi Shankar Sivamani <ksivamani@nvidia.com>

tests/pytorch/test_cuda_graphs.py

@@ -3,7 +3,8 @@
 # See LICENSE for license information.
 
 from dataclasses import dataclass
-from typing import List, Tuple
+import itertools
+from typing import Iterable, List, Tuple, Union
 import pytest
 
 import torch
@@ -88,7 +89,7 @@ def generate_data(
     dpa: bool = False,
     warmup: bool = False,
     return_grad_output: bool = False,
-) -> Tuple[torch.Tensor, torch.Tensor]:
+) -> Tuple[List[torch.Tensor], torch.Tensor]:
     """Generate synthetic data."""
     gen_func = torch.ones if warmup else torch.randn
     if dpa:
@@ -129,14 +130,20 @@ def generate_data(
     return inputs, grad_output
 
 
-def get_outputs(model, output):
+def get_outputs(
+    model: torch.nn.Module,
+    output: Union[torch.Tensor, Iterable[torch.Tensor]],
+) -> List[torch.Tensor]:
     """Return grads and params for comparsion."""
     values = []
     for param in model.parameters():
         values.append(param)
         if param.grad is not None:
             values.append(param.grad)
+    if isinstance(output, torch.Tensor):
         values.append(output)
+    else:
+        values.extend(output)
     return values
 
 
@@ -161,7 +168,7 @@ def _test_cuda_graphs(
     module: str,
     graph_mode: str,
 ) -> List[torch.Tensor]:
-    """Helper function for test."""
+    """Helper function for CUDA graph test."""
     reset_rng_states()
     FP8GlobalStateManager.reset()
     dpa = module == "dpa"
@@ -247,7 +254,7 @@ def _test_cuda_graphs(
         else:
             model = modules[0] if dpa else _Sequential(*modules)
 
-    # Loss function and optimizer.
+    # Optimizer.
     if not dpa:
         optimizer = torch.optim.SGD(model.parameters(), lr=0.001)
 
@@ -312,3 +319,193 @@ def test_gpt_make_graphed_callables(
     # Check that results match
     assert_all_equal(outputs, graph_outputs_mode1)
     assert_all_equal(outputs, graph_outputs_mode2)
+
+
+def _test_cuda_graphs_with_kwargs(
+    *,
+    config: ModelConfig,
+    dtype: torch.dtype,
+    with_graph: bool,
+) -> List[torch.Tensor]:
+    """Simulate Megatron-LM interleaved pipeline parallelism."""
+    reset_rng_states()
+
+    # Initialize model.
+    model = TransformerLayer(
+        config.hidden_size,
+        config.hidden_size,
+        config.num_heads,
+        hidden_dropout=0.0,
+        attention_dropout=0.0,
+        self_attn_mask_type="arbitrary",
+        fuse_qkv_params=True,
+        params_dtype=dtype,
+    )
+
+    # Initialize gradient buffers.
+    for param in model.parameters():
+        param.grad = torch.empty_like(param)
+
+    # Make graphed version of model if needed.
+    if with_graph:
+        attn_mask = torch.zeros(
+            (config.batch_size, 1, config.sequence_length, config.sequence_length),
+            dtype=torch.bool,
+            device="cuda",
+        )
+        model = make_graphed_callables(
+            model,
+            generate_data(config, dtype, warmup=True),
+            sample_kwargs=dict(attention_mask=attn_mask),
+            allow_unused_input=True,
+        )
+
+    # Optimizer.
+    optimizer = torch.optim.SGD(model.parameters(), lr=0.001)
+
+    # Training loop.
+    for _ in range(3):
+        optimizer.zero_grad(set_to_none=False)
+        for grad_accumulation_step in range(2):
+            inputs, grad_output = generate_data(config, dtype, return_grad_output=True)
+            attn_mask = torch.randint(
+                2,
+                (config.batch_size, 1, config.sequence_length, config.sequence_length),
+                dtype=torch.bool,
+                device="cuda",
+            )
+            output = model(*inputs, attention_mask=attn_mask)
+            output.backward(grad_output)
+        optimizer.step()
+
+    return get_outputs(model, output)
+
+
+def test_make_graphed_callables_with_kwargs(
+    dtype: torch.dtype = torch.float32,
+    model: str = "small",
+) -> None:
+    """Test CUDA graphs with keyword arguments."""
+    config = model_configs[model]
+    kwargs = dict(config=config, dtype=dtype)
+    outputs = _test_cuda_graphs_with_kwargs(with_graph=False, **kwargs)
+    graph_outputs = _test_cuda_graphs_with_kwargs(with_graph=True, **kwargs)
+    assert_all_equal(outputs, graph_outputs)
+
+
+def _test_cuda_graphs_with_interleaved_pipeline_parallelism(
+    *,
+    config: ModelConfig,
+    dtype: torch.dtype,
+    with_graph: bool,
+) -> List[torch.Tensor]:
+    """Simulate Megatron-LM interleaved pipeline parallelism."""
+    reset_rng_states()
+
+    # Pipeline parallel configuration.
+    num_layers = 2
+    num_microbatches = 3
+    layer_order = [1, 2, 1, 2, -2, -1, 1, 2, -2, -1, -2, -1]
+
+    # Initialize model.
+    model = torch.nn.ModuleList(
+        [
+            Linear(
+                config.hidden_size,
+                config.hidden_size,
+                params_dtype=dtype,
+            )
+            for _ in range(num_layers)
+        ]
+    )
+
+    # Initialize gradient buffers.
+    for param in model.parameters():
+        param.grad = torch.empty_like(param)
+
+    # Make graphed version of model if needed.
+    layer_forwards = {
+        (i % num_layers, i // num_layers): model[i % num_layers]
+        for i in range(num_layers * num_microbatches)
+    }
+    if with_graph:
+        sample_args = tuple(
+            generate_data(config, dtype, warmup=True) for _ in range(num_layers * num_microbatches)
+        )
+        layer_forwards = make_graphed_callables(
+            tuple(model),
+            sample_args,
+            allow_unused_input=True,
+            _order=layer_order,
+        )
+        layer_forwards = {
+            (i // num_microbatches, i % num_microbatches): forward
+            for i, forward in enumerate(layer_forwards)
+        }
+
+    # Optimizer.
+    optimizer = torch.optim.SGD(model.parameters(), lr=0.001)
+
+    # Training loop.
+    for _ in range(3):
+        optimizer.zero_grad(set_to_none=False)
+
+        # Generate data.
+        inputs = {}
+        grad_outputs = {}
+        for layer_idx in range(num_layers):
+            for microbatch_idx in range(num_microbatches):
+                x, dy = generate_data(config, dtype, return_grad_output=True)
+                idxs = (layer_idx, microbatch_idx)
+                inputs[idxs] = x[0]
+                grad_outputs[idxs] = dy
+
+        # Cache for layer outputs.
+        outputs = {}
+
+        def forward(layer_idx: int, microbatch_idx: int):
+            """Helper function for forward steps"""
+            idxs = (layer_idx, microbatch_idx)
+            outputs[idxs] = layer_forwards[idxs](inputs[idxs])
+
+        def backward(layer_idx: int, microbatch_idx: int):
+            """Helper function for backward steps"""
+            outputs[layer_idx, microbatch_idx].backward(grad_outputs[layer_idx, microbatch_idx])
+
+        # Forward and backward steps.
+        forward(0, 0)
+        forward(1, 0)
+        forward(0, 1)
+        forward(1, 1)
+        backward(1, 0)
+        backward(0, 0)
+        forward(0, 2)
+        forward(1, 2)
+        backward(1, 1)
+        backward(0, 1)
+        backward(1, 2)
+        backward(0, 2)
+
+        # Optimizer step.
+        optimizer.step()
+
+    outputs = [y for _, y in sorted(outputs.items())]
+    return get_outputs(model, outputs)
+
+
+def test_make_graphed_callables_with_interleaved_pipeline_parallelism(
+    dtype: torch.dtype = torch.float16,
+    model: str = "small",
+) -> None:
+    """Test CUDA graphs with Megatron-LM interleaved pipeline parallelism."""
+    config = model_configs[model]
+    kwargs = dict(config=config, dtype=dtype)
+    outputs = _test_cuda_graphs_with_interleaved_pipeline_parallelism(
+        with_graph=False,
+        **kwargs,
+    )
+    graph_outputs = _test_cuda_graphs_with_interleaved_pipeline_parallelism(
+        with_graph=True,
+        **kwargs,
+    )
+    assert_all_equal(outputs, graph_outputs)

transformer_engine/pytorch/graph.py

@@ -3,11 +3,14 @@
 # See LICENSE for license information.
 
 """Functions for CUDA Graphs support in FP8"""
+from typing import Any, Callable, Dict, List, Optional, Tuple, TypeVar, Union
+
 import torch
 from torch.utils._pytree import tree_flatten as _tree_flatten
 from torch.utils._pytree import tree_unflatten as _tree_unflatten
 from torch._C import _graph_pool_handle
 
+from transformer_engine.common.recipe import DelayedScaling
 from .fp8 import (
     fp8_autocast,
     FP8GlobalStateManager,
@@ -22,6 +25,9 @@ __all__ = ["make_graphed_callables"]
 
 _IS_GRAPH_CAPTURING = False
 
+_T = TypeVar("_T")
+SingleOrTuple = Union[_T, Tuple[_T, ...]]
+
 
 def set_capture_start() -> None:
     """Record beginning of `make_graphed_callables`."""
@@ -48,13 +54,14 @@ def graph_pool_handle():
 
 
 def _make_graphed_callables(
-    callables,
-    sample_args,
-    num_warmup_iters=3,
-    allow_unused_input=False,
-    fp8_weight_caching=False,
-    _order=None,
-):
+    callables: SingleOrTuple[Callable],
+    sample_args: SingleOrTuple[Tuple[torch.Tensor, ...]],
+    num_warmup_iters: int = 3,
+    allow_unused_input: bool = False,
+    fp8_weight_caching: bool = False,
+    sample_kwargs: Optional[SingleOrTuple[Dict[str, Any]]] = None,
+    _order: Optional[List[int]] = None,
+) -> SingleOrTuple[Callable]:
     """
     Helper method for `make_graphed_callables`
     """
@@ -65,16 +72,38 @@ def _make_graphed_callables(
             "caching. Please set `cache_enabled=False`."
         )
 
-    just_one_callable = False
+    # Default is to pass no kwargs to callables
+    if sample_kwargs is None:
+        if isinstance(callables, tuple):
+            sample_kwargs = tuple({} for _ in range(len(sample_args)))
+        else:
+            sample_kwargs = {}
 
+    # Canonicalize args as tuples
+    just_one_callable = False
     if not isinstance(callables, tuple):
         just_one_callable = True
         callables = (callables,)
         sample_args = (sample_args,)
+        sample_kwargs = (sample_kwargs,)
 
-    flatten_sample_args = []
-    if _order is not None:
-        # order is a list containing 1..model_chunk values in the order of microbatch schedule
+    # Check sizes of args
+    if _order is None:
+        assert len(sample_args) == len(callables)
+        assert len(sample_kwargs) == len(callables)
+    else:
+        # Custom logic for interleaved pipeline parallelism
+        # Note: This is tightly coupled with the Megatron-core
+        # implementation of interleaved pipeline parallelism at
+        # https://github.com/NVIDIA/Megatron-LM/blob/main/megatron/core/pipeline_parallel/schedules.py.
+        # Note: The model is assumed to consist of layers
+        # (corresponding to callables) that are grouped into
+        # equally-sized model chunks. _order is a list of chunk
+        # indices (1-indexed) that indicates the order in which the
+        # layers are evaluated. Positive values indicate forward
+        # passes and negative values indicate backward passes. Each
+        # entry in sample_args corresponds to one of the forward
+        # passes.
         num_model_chunks = max(_order)
         num_microbatches = len(_order) // num_model_chunks // 2
         assert num_model_chunks * num_microbatches * 2 == len(_order)
@@ -90,10 +119,13 @@ def _make_graphed_callables(
             f"Expected {num_model_chunks * num_microbatches}"
             + f"args tuple, but got {len(sample_args)}."
         )
+        assert len(sample_kwargs) == len(sample_args)
 
     if fp8_weight_caching:
+        # Initialize flag that controls FP8 weight updates
         FP8GlobalStateManager.set_skip_fp8_weight_update_tensor(False)
 
+    # Check callables
     for c in callables:
         if isinstance(c, torch.nn.Module):
             assert (
@@ -110,9 +142,14 @@ def _make_graphed_callables(
                 + ":func:`~make_graphed_callables`, only parameters may be trainable. "
                 + "All buffers must have ``requires_grad=False``."
             )
-    for args in sample_args:
+
+    # Flatten callable arguments
+    per_callable_kwargs_keys = [list(kwargs.keys()) for kwargs in sample_kwargs]
+    flatten_sample_args = []
+    for args, kwargs, kwargs_keys in zip(sample_args, sample_kwargs, per_callable_kwargs_keys):
         flatten_arg, _ = _tree_flatten(args)
-        flatten_sample_args.append(tuple(flatten_arg))
+        flatten_kwarg, _ = _tree_flatten([kwargs[key] for key in kwargs_keys])
+        flatten_sample_args.append(tuple(flatten_arg + flatten_kwarg))
         assert all(isinstance(arg, torch.Tensor) for arg in flatten_arg), (
             "In the beta API, sample_args "
             + "for each callable must contain only Tensors. Other types are not allowed."
@@ -120,6 +157,10 @@ def _make_graphed_callables(
 
     # If a callable is an nn.Module, its graph's full input surface is the args the user explicitly
     # passes to forward (ie, its sample_args) AND the module's parameter attributes.
+    # Note: These per_callable_* variables are not actually
+    # per-callable, but per-forward-pass (see description of _order).
+    # The names are kept for consistency with
+    # torch.cuda.make_graphed_callables.
     per_callable_len_user_args = [len(args) for args in flatten_sample_args]
     if _order is None:
         per_callable_module_params = [
@@ -144,6 +185,7 @@ def _make_graphed_callables(
     fwd_graphs = [torch.cuda.CUDAGraph() for _ in range(len(flatten_sample_args))]
     bwd_graphs = [torch.cuda.CUDAGraph() for _ in range(len(flatten_sample_args))]
     graph_callables = [None for _ in range(len(flatten_sample_args))]
+
     # For cases with multiple active RNG states, e.g. TP.
     if graph_safe_rng_available():
         for _, state in get_all_rng_states().items():
@@ -158,11 +200,12 @@ def _make_graphed_callables(
     # from ending up in any captures.
     torch.cuda.synchronize()
     with torch.cuda.stream(torch.cuda.Stream()):
-        for c_i, func in enumerate(callables):
-            args = sample_args[c_i]
-            static_input_surface = per_callable_static_input_surfaces[c_i]
+        for func_idx, func in enumerate(callables):
+            args = sample_args[func_idx]
+            kwargs = sample_kwargs[func_idx]
+            static_input_surface = per_callable_static_input_surfaces[func_idx]
             for _ in range(num_warmup_iters):
-                outputs, _ = _tree_flatten(func(*args))
+                outputs, _ = _tree_flatten(func(*args, **kwargs))
                 grad_inputs = torch.autograd.grad(
                     outputs=tuple(o for o in outputs if o.requires_grad),
                     inputs=tuple(i for i in static_input_surface if i.requires_grad),
@@ -194,9 +237,10 @@ def _make_graphed_callables(
                         fwd_idx[m_chunk] * num_layers + l_no
                     )
                     args = sample_args[per_callable_fwd_idx]
+                    kwargs = sample_kwargs[per_callable_fwd_idx]
                     fwd_graph = fwd_graphs[per_callable_fwd_idx]
                     with torch.cuda.graph(fwd_graph, pool=mempool):
-                        outputs = func(*args)
+                        outputs = func(*args, **kwargs)
                     flatten_outputs, spec = _tree_flatten(outputs)
                     per_callable_static_outputs[per_callable_fwd_idx] = tuple(flatten_outputs)
                     per_callable_output_unflatten_spec[per_callable_fwd_idx] = spec
@@ -245,9 +289,9 @@ def _make_graphed_callables(
         per_callable_static_outputs = []
         per_callable_output_unflatten_spec = []
         graph_id = 0
-        for func, args, fwd_graph in zip(callables, sample_args, fwd_graphs):
+        for func, args, kwargs, fwd_graph in zip(callables, sample_args, sample_kwargs, fwd_graphs):
             with torch.cuda.graph(fwd_graph, pool=mempool):
-                outputs = func(*args)
+                outputs = func(*args, **kwargs)
             graph_callables[graph_id] = func
             graph_id += 1
 
@@ -300,6 +344,7 @@ def _make_graphed_callables(
         fwd_graph,
         bwd_graph,
         module_params,
+        kwargs_keys,
         len_user_args,
         output_unflatten_spec,
         static_input_surface,
@@ -312,14 +357,18 @@ def _make_graphed_callables(
 
             @staticmethod
             def forward(ctx, skip_fp8_weight_update, *inputs):
-                # At this stage, only the user args may (potentially) be new tensors.
+
+                # Set flag for whether to update FP8 weight updates
                 ctx.is_first_module = FP8GlobalStateManager.is_first_fp8_module()
                 if ctx.is_first_module and skip_fp8_weight_update is not None:
                     FP8GlobalStateManager.set_skip_fp8_weight_update_tensor(skip_fp8_weight_update)
 
+                # Copy values from new tensors into static tensors
                 for i in range(len_user_args):
                     if static_input_surface[i].data_ptr() != inputs[i].data_ptr():
                         static_input_surface[i].copy_(inputs[i])
+
+                # Replay forward graph
                 fwd_graph.replay()
                 assert isinstance(static_outputs, tuple)
                 return tuple(o.detach() for o in static_outputs)
@@ -327,6 +376,8 @@ def _make_graphed_callables(
             @staticmethod
             @torch.autograd.function.once_differentiable
             def backward(ctx, *grads):
+
+                # Replay backward graph
                 assert len(grads) == len(static_grad_outputs)
                 for g, grad in zip(static_grad_outputs, grads):
                     if g is not None:
@@ -336,6 +387,7 @@ def _make_graphed_callables(
                             g.copy_(grad)
                 bwd_graph.replay()
 
+                # Update FP8 scale factors if needed
                 if ctx.is_first_module:
                     FP8GlobalStateManager.reduce_and_update_fp8_tensors(forward=False)
 
@@ -346,10 +398,8 @@ def _make_graphed_callables(
                 )
 
         def functionalized(*user_args, **user_kwargs):
-            # Runs the autograd function with inputs == all
-            # inputs to the graph that might require grad
-            # (explicit user args + module parameters)
-            # Assumes module params didn't change since capture.
+
+            # Decide whether to update FP8 weights
             skip_fp8_weight_update = None
             if fp8_weight_caching:
                 assert "is_first_microbatch" in user_kwargs and isinstance(
@@ -358,8 +408,22 @@ def _make_graphed_callables(
 
                 skip_fp8_weight_update = not user_kwargs["is_first_microbatch"]
 
+            # Check that required kwargs are provided
+            for key in kwargs_keys:
+                if key not in user_kwargs:
+                    raise TypeError(
+                        f"Graphed callable was initialized with kwarg {key} ,"
+                        "but it was not provided in graph replay"
+                    )
+
+            # Runs the autograd function with inputs == all inputs to
+            # the graph that might require grad (explicit user args +
+            # module parameters)
+            # Assumes module params didn't change since capture.
             flatten_user_args, _ = _tree_flatten(user_args)
-            out = Graphed.apply(skip_fp8_weight_update, *(tuple(flatten_user_args) + module_params))
+            flatten_user_kwargs, _ = _tree_flatten([user_kwargs[key] for key in kwargs_keys])
+            func_args = tuple(flatten_user_args) + tuple(flatten_user_kwargs) + module_params
+            out = Graphed.apply(skip_fp8_weight_update, *func_args)
             return _tree_unflatten(out, output_unflatten_spec)
 
         return functionalized
@@ -371,6 +435,7 @@ def _make_graphed_callables(
             fwd_graphs[i],
             bwd_graphs[i],
             per_callable_module_params[i],
+            per_callable_kwargs_keys[i],
             per_callable_len_user_args[i],
             per_callable_output_unflatten_spec[i],
             per_callable_static_input_surfaces[i],
@@ -443,25 +508,42 @@ def restore_fp8_tensors(modules, fp8_tensors):
 
 
 def make_graphed_callables(
-    modules,
-    sample_args,
-    num_warmup_iters=3,
-    allow_unused_input=False,
-    fp8_enabled=False,
-    fp8_calibrating=False,
-    fp8_recipe=None,
-    fp8_weight_caching=False,
-    _order=None,
-):
+    modules: SingleOrTuple[Callable],
+    sample_args: SingleOrTuple[Tuple[torch.Tensor, ...]],
+    num_warmup_iters: int = 3,
+    allow_unused_input: bool = False,
+    sample_kwargs: Optional[SingleOrTuple[Dict[str, Any]]] = None,
+    fp8_enabled: bool = False,
+    fp8_calibrating: bool = False,
+    fp8_recipe: Optional[DelayedScaling] = None,
+    fp8_weight_caching: bool = False,
+    _order: Optional[List[int]] = None,
+) -> Union[Callable, Tuple[Callable, ...]]:
     """
-    A version of PyTorch's `make_graphed_callables` utility function with support for
-    TransformerEngine modules and FP8. Please see the original version in upstream PyTorch
-    `here <https://pytorch.org/docs/stable/generated/torch.cuda.make_graphed_callables.html>`_
-    for extensive documentation. The documentation for additional parameters which are
-    specific to FP8 are given below.
-
-    FP8 specific parameters
-    -----------------------
+    Make CUDA graph version of Transformer Engine modules
+
+    A variation of PyTorch's `make_graphed_callables` utility function
+    with support for Transformer Engine modules and FP8. Please see
+    the
+    `original PyTorch implementation <https://pytorch.org/docs/stable/generated/torch.cuda.make_graphed_callables.html>`_
+    for more documentation.
+
+    Graphing parameters
+    -------------------
+    modules: (tuple of) callable
+             Callable or callables to graph.
+    sample_args: (tuple of) tuple of torch.Tensor
+                 Positional arguments to callable(s).
+    num_warmup_iters: int, default = 3
+                      Number of warmup iterations.
+    allow_unused_input: bool, default = `False`
+                        Whether to handle case where callable inputs
+                        and outputs are disconnected in compute graph.
+    sample_kwargs: (tuple of) dict, optional
+                   Keyword arguments to callable(s)
+
+    FP8-related parameters
+    ----------------------
     fp8_enabled: bool, default = `True`
                  whether or not to enable fp8
     fp8_calibrating: bool, default = `False`
@@ -478,6 +560,7 @@ def make_graphed_callables(
                         using TE's `fp8_model_init` API and using an FP8 aware optimizer, this arg
                         must be set to `False` if calculating weight transposes' outside TE, e.g.,
                         in the optimizer step.
+
     """
     set_capture_start()
 
@@ -532,6 +615,7 @@ def make_graphed_callables(
         num_warmup_iters=num_warmup_iters,
         allow_unused_input=allow_unused_input,
         fp8_weight_caching=fp8_weight_caching,
+        sample_kwargs=sample_kwargs,
         _order=_order,
     )