[Compiler Toolkit] Avoid DTensorize BlockMask for FlexAttention (#1952)

```
    # TODO: When using flex_attention, BlockMask would show up in kwargs,
    # and it's unclear how to convert it to DTensor. If I use to_dtensor,
    # it would fail with Dynamo Error: P2011360347
    # dt_kwargs = tree_map(to_dtensor, kwargs)
```

Author: SherlockNoMad

torchtitan/experiments/compiler_toolkit/common_utils.py

@@ -6,6 +6,10 @@
 
 from contextlib import contextmanager
 
+import torch
+from torch.distributed.tensor import DTensor, Replicate
+from torch.utils._pytree import tree_map
+
 from torchtitan.config import JobConfig
 
 
@@ -18,3 +22,21 @@ def disable_compile(job_config: JobConfig):
         yield
     finally:
         job_config.compile.enable = original_value
+
+
+def parallelize_inputs(world_mesh, args, kwargs):
+    def to_dtensor(tensor):
+        if isinstance(tensor, torch.Tensor):
+            return DTensor.from_local(tensor, world_mesh["tp"], [Replicate()])
+        return tensor
+
+    dt_args = tree_map(to_dtensor, args)
+
+    # TODO: When using flex_attention, BlockMask would show up in kwargs,
+    # and it's unclear how to convert it to DTensor. If I use to_dtensor,
+    # it would fail with Dynamo Error: P2011360347
+    # dt_kwargs = tree_map(to_dtensor, kwargs)
+
+    dt_kwargs = kwargs
+
+    return dt_args, dt_kwargs

torchtitan/experiments/compiler_toolkit/deepseek_v3/parallelize.py

@@ -11,14 +11,16 @@
 from torch._functorch.aot_autograd import aot_compile_joint_with_descriptors
 from torch._guards import tracing
 
-from torch.distributed.tensor import DTensor, Replicate
+from torch.distributed.tensor import DTensor
 
 from torch.fx.traceback import annotate_fn
-from torch.utils._pytree import tree_map
 from torchtitan.config import JobConfig
 from torchtitan.distributed import ParallelDims
 from torchtitan.distributed.expert_parallel import ExpertParallel
-from torchtitan.experiments.compiler_toolkit.common_utils import disable_compile
+from torchtitan.experiments.compiler_toolkit.common_utils import (
+    disable_compile,
+    parallelize_inputs,
+)
 
 from torchtitan.experiments.compiler_toolkit.graph_utils import (
     CompiledModule,
@@ -75,18 +77,6 @@ def wrapper_fn(args, kwargs):
     return wrapper_fn
 
 
-def parallelize_inputs(world_mesh, args, kwargs):
-    def to_dtensor(tensor):
-        if isinstance(tensor, torch.Tensor):
-            return DTensor.from_local(tensor, world_mesh["tp"], [Replicate()])
-        return tensor
-
-    dt_args = tree_map(to_dtensor, args)
-    dt_kwargs = tree_map(to_dtensor, kwargs)
-
-    return dt_args, dt_kwargs
-
-
 def annotate_model() -> None:
     # annotate the MoE with dispatch, compute and combine
     ExpertParallel._token_dispatch = annotate_fn({"EP": "dispatch"})(

torchtitan/experiments/compiler_toolkit/llama3/parallelize.py

@@ -9,13 +9,15 @@
 from torch._functorch.aot_autograd import aot_compile_joint_with_descriptors
 from torch._guards import tracing
 
-from torch.distributed.tensor import DTensor, Replicate
+from torch.distributed.tensor import DTensor
 from torch.fx.passes.regional_inductor import regional_inductor
-from torch.utils._pytree import tree_map
 
 from torchtitan.config import JobConfig
 from torchtitan.distributed import ParallelDims
-from torchtitan.experiments.compiler_toolkit.common_utils import disable_compile
+from torchtitan.experiments.compiler_toolkit.common_utils import (
+    disable_compile,
+    parallelize_inputs,
+)
 
 from torchtitan.experiments.compiler_toolkit.graph_utils import (
     CompiledModule,
@@ -78,18 +80,6 @@ def wrapper_fn(args, kwargs):
     return wrapper_fn
 
 
-def parallelize_inputs(world_mesh, args, kwargs):
-    def to_dtensor(tensor):
-        if isinstance(tensor, torch.Tensor):
-            return DTensor.from_local(tensor, world_mesh["tp"], [Replicate()])
-        return tensor
-
-    dt_args = tree_map(to_dtensor, args)
-    dt_kwargs = tree_map(to_dtensor, kwargs)
-
-    return dt_args, dt_kwargs
-
-
 def annotate_model() -> None:
     from torch.fx.traceback import annotate_fn
     from torchtitan.models.attention import FlexAttentionWrapper