ThunderFX: Add split reason and submodule structure in repro script (#…

…1461)

thunder/dynamo/compiler.py

@@ -121,6 +121,7 @@ def save_reproducer_to_folder(self, reproducer_folder: str | PathLike, use_pytes
             ):
                 reproducer(
                     cur_module,
+                    subgraph_info,
                     self.thunder_options,
                     example_input,
                     reproducer_folder,

thunder/dynamo/utils.py

@@ -728,6 +728,7 @@ def thunder_options_to_str(thunder_options: dict) -> str:
 
 def reproducer(
     gm: torch.fx.GraphModule,
+    subgraph_info: SubgraphInfo,
     thunder_options: dict,
     args: tuple[torch.Tensor | ExampleInputMetaData],
     folder: str | os.PathLike,
@@ -742,6 +743,17 @@ def reproducer(
     readable = _readable(gm, "DynamoModule", print_output=False)
     has_cuda_args = any(hasattr(arg, "device") and arg.device.type == "cuda" for arg in args)
     thunder_options_str = thunder_options_to_str(thunder_options)
+
+    # split reason
+    if subgraph_info.split_reasons:
+        num_submodules = len(subgraph_info.submodule_to_compiled_functions)
+        num_thunder_submodules = len(subgraph_info.thunder_compiled_fns)
+        split_reason_str = f"The original graph is split into {num_submodules} subgraphs, {num_thunder_submodules} of which are run by thunder.jit.\n"
+        split_reason_str += f"The structure of the split module:\n{subgraph_info.split_graph_module}\n"
+        split_reason_str += f"Split Reasons:\n"
+        for id, split_reason in enumerate(subgraph_info.split_reasons):
+            split_reason_str += f"  Split Reason {id}:\n    {split_reason.info}\n"
+
     with open(folder / f"{graph_name}.py", "w") as f:
         comment_str = f'''"""
 Environment information get from `torch.utils.collect_env.get_pretty_env_info()`:
@@ -750,10 +762,12 @@ def reproducer(
 Versions of Thunder related libraries:
 {thunder_pkgs}
 
-The torch.fx.Graph:
-{gm.graph}
-"""
 '''
+        if subgraph_info.split_reasons:
+            comment_str += f'{split_reason_str}"""\n'
+            del split_reason_str
+        else:
+            comment_str += '"""\n'
         if use_pytest_benchmark:
             comment_str += f"""# NOTE: This script requires `pytest-benchmark==4.0.0` to be installed.
 # To execute the script, run `pytest {graph_name}.py`"""

thunder/tests/test_dynamo.py

@@ -885,3 +885,38 @@ def forward(self, x):
 
     # No assertion error
     copy_gm = copy.deepcopy(original_split_gm)
+
+
+@instantiate(
+    dtypes=NOTHING,
+    executors=[DynamoThunderExecutor],
+    decorators=(pytest.mark.parametrize("use_pytest_benchmark", (True, False), ids=("benchmark", "repro")),),
+)
+def test_dynamo_reproducer_split(executor, device: str, dtype: dtypes.dtype, use_pytest_benchmark, tmp_path):
+    x = torch.ones(2, 2, device=device, dtype=dtype, requires_grad=True)
+
+    backend = ThunderCompiler()
+
+    def func(x):
+        # torch.sinc has automatic fallback registered,
+        # so that operation will be given to inductor.
+        x = x.exp()
+        y = torch.sinc(x) + torch.cos(x)
+        y = y + torch.sinc(x)
+        return y + 1
+
+    cfunc = torch.compile(func, backend=backend)
+    actual = cfunc(x)
+    backend.save_reproducer_to_folder(tmp_path, use_pytest_benchmark)
+
+    def check(file_name, cmd):
+        assert os.path.exists(file_name)
+        result = run([cmd, file_name], capture_output=True, text=True)
+        assert result.returncode == 0, f"Reproducer {file_name} failed with return code {result.returncode}"
+
+    s1 = f"{tmp_path}/graph0_thunder_0.py"
+    s2 = f"{tmp_path}/graph0_thunder_2.py"
+    s3 = f"{tmp_path}/graph0_thunder_4.py"
+    cmd = "pytest" if use_pytest_benchmark else "python"
+    for fname in [s1, s2, s3]:
+        check(fname, cmd)