[torch.compile] limit inductor threads and lazy import quant (#10482)

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

tests/quantization/utils.py

@@ -1,4 +1,4 @@
-from vllm.model_executor.layers.quantization import QUANTIZATION_METHODS
+from vllm.model_executor.layers.quantization import get_quantization_config
 from vllm.platforms import current_platform
 
 
@@ -10,6 +10,6 @@ def is_quant_method_supported(quant_method: str) -> bool:
     capability = current_platform.get_device_capability()
     assert capability is not None
 
-    min_capability = QUANTIZATION_METHODS[quant_method].get_min_capability()
+    min_capability = get_quantization_config(quant_method).get_min_capability()
 
     return capability.to_int() >= min_capability

tests/test_lazy_torch_compile.py

@@ -0,0 +1,68 @@
+# Description: Test the lazy import module
+# The utility function cannot be placed in `vllm.utils`
+# this needs to be a standalone script
+
+import contextlib
+import dataclasses
+import sys
+import traceback
+from typing import Callable, Generator
+
+
+@dataclasses.dataclass
+class BlameResult:
+    found: bool = False
+    trace_stack: str = ""
+
+
+@contextlib.contextmanager
+def blame(func: Callable) -> Generator[BlameResult, None, None]:
+    """
+    Trace the function calls to find the first function that satisfies the
+    condition. The trace stack will be stored in the result.
+
+    Usage:
+
+    ```python
+    with blame(lambda: some_condition()) as result:
+        # do something
+    
+    if result.found:
+        print(result.trace_stack)
+    """
+    result = BlameResult()
+
+    def _trace_calls(frame, event, arg=None):
+        nonlocal result
+        if event in ['call', 'return']:
+            # for every function call or return
+            try:
+                # Temporarily disable the trace function
+                sys.settrace(None)
+                # check condition here
+                if not result.found and func():
+                    result.found = True
+                    result.trace_stack = "".join(traceback.format_stack())
+                # Re-enable the trace function
+                sys.settrace(_trace_calls)
+            except NameError:
+                # modules are deleted during shutdown
+                pass
+        return _trace_calls
+
+    sys.settrace(_trace_calls)
+
+    yield result
+
+    sys.settrace(None)
+
+
+module_name = "torch._inductor.async_compile"
+
+with blame(lambda: module_name in sys.modules) as result:
+    import vllm  # noqa
+
+assert not result.found, (f"Module {module_name} is already imported, the"
+                          f" first import location is:\n{result.trace_stack}")
+
+print(f"Module {module_name} is not imported yet")