[torch.compile] reorganize the cache directory to support compiling multiple models (#19064)

Signed-off-by: youkaichao <youkaichao@gmail.com>

vllm/config.py

@@ -4666,10 +4666,13 @@ class VllmConfig:
 
 
 _current_vllm_config: Optional[VllmConfig] = None
+_current_prefix: Optional[str] = None
 
 
 @contextmanager
-def set_current_vllm_config(vllm_config: VllmConfig, check_compile=False):
+def set_current_vllm_config(vllm_config: VllmConfig,
+                            check_compile=False,
+                            prefix: Optional[str] = None):
     """
     Temporarily set the current vLLM config.
     Used during model initialization.
@@ -4677,12 +4680,14 @@ def set_current_vllm_config(vllm_config: VllmConfig, check_compile=False):
     so that all modules can access it, e.g. custom ops
     can access the vLLM config to determine how to dispatch.
     """
-    global _current_vllm_config
+    global _current_vllm_config, _current_prefix
     old_vllm_config = _current_vllm_config
+    old_prefix = _current_prefix
     from vllm.compilation.counter import compilation_counter
     num_models_seen = compilation_counter.num_models_seen
     try:
         _current_vllm_config = vllm_config
+        _current_prefix = prefix
         yield
     except Exception:
         raise
@@ -4706,6 +4711,7 @@ def set_current_vllm_config(vllm_config: VllmConfig, check_compile=False):
                 vllm_config.model_config.model)
     finally:
         _current_vllm_config = old_vllm_config
+        _current_prefix = old_prefix
 
 
 def get_current_vllm_config() -> VllmConfig:
@@ -4719,6 +4725,15 @@ def get_current_vllm_config() -> VllmConfig:
     return _current_vllm_config
 
 
+def get_current_model_prefix() -> str:
+    """
+    Get the prefix of the model that's currently being initialized.
+    """
+    assert _current_prefix is not None, \
+        "Current model prefix is not set. "
+    return _current_prefix
+
+
 def contains_object_print(text):
     """
     Check if the text looks like a printed Python object, e.g.