[torch.compile] disable logging when cache is disabled (#12043)

Signed-off-by: youkaichao <[email protected]>

vllm/compilation/backends.py

@@ -251,15 +251,27 @@ def _check_can_cache(*args, **kwargs):
         def _get_shape_env() -> AlwaysHitShapeEnv:
             return AlwaysHitShapeEnv()
 
-        with patch(# for hijacking the hash of the compiled graph
-                "torch._inductor.codecache.compiled_fx_graph_hash",
-                hijack_compiled_fx_graph_hash), \
-            patch(# for providing a dummy shape environment
-                "torch._inductor.codecache.FxGraphCache._get_shape_env",
-                 _get_shape_env), \
-            patch(# for forcing the graph to be cached
-                "torch._inductor.codecache.FxGraphCache._check_can_cache",
-                _check_can_cache):
+        with ExitStack() as stack:
+            if not cache_data.disabled:
+                # compilation cache is enabled, patch several functions
+
+                # for hijacking the hash of the compiled graph
+                stack.enter_context(
+                    patch("torch._inductor.codecache.compiled_fx_graph_hash",
+                          hijack_compiled_fx_graph_hash))
+
+                # for providing a dummy shape environment
+                stack.enter_context(
+                    patch(
+                        "torch._inductor.codecache.FxGraphCache._get_shape_env",
+                        _get_shape_env))
+
+                # for forcing the graph to be cached
+                stack.enter_context(
+                    patch(
+                        "torch._inductor.codecache.FxGraphCache._check_can_cache",
+                        _check_can_cache))
+
             compiled_graph = compile_fx(graph,
                                         example_inputs,
                                         config_patches=current_config)