Optimize configuration access with LRU cache in custom ops (vllm-project#22204)

Signed-off-by: zitian zhao <zitian.zhao@tencentmusic.com>

Author: skyloevil

vllm/config.py

@@ -15,7 +15,7 @@
 from contextlib import contextmanager
 from dataclasses import (MISSING, Field, asdict, field, fields, is_dataclass,
                          replace)
-from functools import cached_property
+from functools import cached_property, lru_cache
 from importlib.util import find_spec
 from typing import (TYPE_CHECKING, Any, Callable, ClassVar, Literal, Optional,
                     Protocol, TypeVar, Union, cast, get_args)
@@ -5123,6 +5123,14 @@ def set_current_vllm_config(vllm_config: VllmConfig,
     finally:
         _current_vllm_config = old_vllm_config
         _current_prefix = old_prefix
+        # Clear the compilation config cache when context changes
+        get_cached_compilation_config.cache_clear()
+
+
+@lru_cache(maxsize=1)
+def get_cached_compilation_config():
+    """Cache config to avoid repeated calls to get_current_vllm_config()"""
+    return get_current_vllm_config().compilation_config
 
 
 def get_current_vllm_config() -> VllmConfig:

vllm/model_executor/custom_op.py

@@ -5,7 +5,7 @@
 
 import torch.nn as nn
 
-from vllm.config import get_current_vllm_config
+from vllm.config import get_cached_compilation_config
 from vllm.logger import init_logger
 from vllm.platforms import current_platform
 
@@ -86,7 +86,7 @@ def forward_oot(self, *args, **kwargs):
     def dispatch_forward(self):
         # NOTE(woosuk): Here we assume that vLLM was built for only one
         # specific backend. Currently, we do not support dynamic dispatching.
-        compilation_config = get_current_vllm_config().compilation_config
+        compilation_config = get_cached_compilation_config()
         enabled = self.enabled()
         if enabled:
             compilation_config.enabled_custom_ops.update([self.__class__.name])
@@ -115,7 +115,7 @@ def dispatch_forward(self):
     @classmethod
     def enabled(cls) -> bool:
         # if no name, then it was not registered
-        compilation_config = get_current_vllm_config().compilation_config
+        compilation_config = get_cached_compilation_config()
         custom_ops = compilation_config.custom_ops
         if not hasattr(cls, "name"):
             logger.warning_once(
@@ -138,7 +138,7 @@ def default_on() -> bool:
         Specifying 'all' or 'none' in custom_op takes precedence.
         """
         from vllm.config import CompilationLevel
-        compilation_config = get_current_vllm_config().compilation_config
+        compilation_config = get_cached_compilation_config()
         default_on = (compilation_config.level < CompilationLevel.PIECEWISE
                       or not compilation_config.use_inductor)
         count_none = compilation_config.custom_ops.count("none")