Revert "[compile] Initialize passes at VllmBackend init" (#37733)

tests/test_config.py

@@ -32,9 +32,9 @@ from vllm.platforms import current_platform
 
 def test_compile_config_repr_succeeds():
     # setup: VllmBackend mutates the config object
-    # Note: VllmBackend.__init__ already calls configure_post_pass()
     config = VllmConfig()
-    _ = VllmBackend(config)
+    backend = VllmBackend(config)
+    backend.configure_post_pass()
 
     # test that repr(config) succeeds
     val = repr(config)

vllm/compilation/backends.py

@@ -836,18 +836,8 @@ class VllmBackend:
         # in future we need PostGradPassManager.uuid() to be executed
         # only at compile time.
         self.inductor_config = deepcopy(self.compilation_config.inductor_compile_config)
-
-        # Configure post-grad passes (including AllReduceFusionPass) during
-        # backend init rather than at torch.compile time, so that expensive
-        # one-time setup (e.g. FlashInfer workspace allocation) is not
-        # attributed to compilation latency.
-        start = time.time()
-        self.configure_post_pass()
-        logger.info_once(
-            "Post-grad pass configuration time: %.2f s",
-            time.time() - start,
-            scope="local",
-        )
+        # `torch.compile` is JIT compiled, so we don't need to
+        # do anything here
 
     def collect_standalone_compile_artifacts(
         self,
@@ -1128,6 +1118,7 @@ class VllmBackend:
         assert not self._called, "VllmBackend can only be called once"
 
         self.graph = graph
+        self.configure_post_pass()
 
         if self.compilation_config.use_inductor_graph_partition:
             # Let Inductor decide partitioning; avoid FX-level pre-splitting.

vllm/compilation/decorators.py

@@ -380,11 +380,6 @@ def _support_torch_compile(
         compilation_counter.num_models_seen += 1
         self.compiled = False
 
-        # Skip if a parent class's @support_torch_compile already
-        # initialized the compile wrapper
-        if hasattr(self, "_compiled_callable"):
-            return
-
         # Handled by monkeypatching `TorchCompileWithNoGuardsWrapper` into base class
         TorchCompileWithNoGuardsWrapper.__init__(
             self,