Add option to use torch._inductor.standalone_compile (#17057)

Signed-off-by: rzou <zou3519@gmail.com>

vllm/compilation/backends.py

@@ -17,7 +17,8 @@ from vllm.config import CompilationConfig, VllmConfig
 from vllm.logger import init_logger
 from vllm.utils import weak_ref_tensors
 
-from .compiler_interface import EagerAdaptor, InductorAdaptor
+from .compiler_interface import (CompilerInterface, EagerAdaptor,
+                                 InductorAdaptor, InductorStandaloneAdaptor)
 from .counter import compilation_counter
 from .inductor_pass import InductorPass
 from .monitor import end_monitoring_torch_compile
@@ -26,6 +27,19 @@ from .pass_manager import PostGradPassManager
 logger = init_logger(__name__)
 
 
+def make_compiler(compilation_config: CompilationConfig) -> CompilerInterface:
+    if compilation_config.use_inductor:
+        if envs.VLLM_TEST_STANDALONE_COMPILE:
+            logger.info("Using InductorStandaloneAdaptor")
+            return InductorStandaloneAdaptor()
+        else:
+            logger.info("Using InductorAdaptor")
+            return InductorAdaptor()
+    else:
+        logger.info("Using EagerAdaptor")
+        return EagerAdaptor()
+
+
 class CompilerManager:
     """
     A manager to manage the compilation process, including
@@ -41,11 +55,11 @@ class CompilerManager:
     support int as key.
     """
 
-    def __init__(self, use_inductor: bool):
+    def __init__(self, compilation_config: CompilationConfig):
         self.cache: Dict[Tuple[Optional[int], int, str], Any] = dict()
-        cls = InductorAdaptor if use_inductor else EagerAdaptor
-        self.compiler = cls()
         self.is_cache_updated = False
+        self.compilation_config = compilation_config
+        self.compiler = make_compiler(compilation_config)
 
     def compute_hash(self, vllm_config: VllmConfig) -> str:
         return self.compiler.compute_hash(vllm_config)
@@ -123,8 +137,15 @@ class CompilerManager:
 
         # no compiler cached the graph, or the cache is disabled,
         # we need to compile it
+        if isinstance(self.compiler, InductorAdaptor):
+            # Let compile_fx generate a key for us
+            maybe_key = None
+        else:
+            maybe_key = \
+                f"artifact_shape_{runtime_shape}_subgraph_{graph_index}"
         compiled_graph, handle = self.compiler.compile(
-            graph, example_inputs, additional_inductor_config, runtime_shape)
+            graph, example_inputs, additional_inductor_config, runtime_shape,
+            maybe_key)
 
         assert compiled_graph is not None, "Failed to compile the graph"
 
@@ -336,7 +357,7 @@ class VllmBackend:
         self.compilation_config = vllm_config.compilation_config
 
         self.compiler_manager: CompilerManager = CompilerManager(
-            self.compilation_config.use_inductor)
+            self.compilation_config)
 
         # `torch.compile` is JIT compiled, so we don't need to
         # do anything here

vllm/compilation/compiler_interface.py

@@ -50,7 +50,8 @@ class CompilerInterface:
         graph: fx.GraphModule,
         example_inputs: List[Any],
         compiler_config: Dict[str, Any],
-        runtime_shape: Optional[int] = None
+        runtime_shape: Optional[int] = None,
+        key: Optional[str] = None,
     ) -> Tuple[Optional[Callable], Optional[Any]]:
         """
         Compile the graph with the given example inputs and compiler config,
@@ -71,6 +72,10 @@ class CompilerInterface:
         If the compiler doesn't support caching, it should return None for the
         handle. If the compiler fails to compile the graph, it should return
         None for the compiled function as well.
+
+        `key` is required for StandaloneInductorAdapter, it specifies where to
+        save the compiled artifact. The compiled artifact gets saved to
+        `cache_dir/key`.
         """
         return None, None
 
@@ -127,13 +132,7 @@ class AlwaysHitShapeEnv:
         return ""
 
 
-class InductorAdaptor(CompilerInterface):
-    """
-    The adaptor for the Inductor compiler, version 2.5 and 2.6.
-    """
-    name = "inductor"
-
-    def compute_hash(self, vllm_config: VllmConfig) -> str:
+def get_inductor_factors() -> List[Any]:
     factors: List[Any] = []
     # summarize system state
     from torch._inductor.codecache import CacheBase
@@ -144,6 +143,97 @@ class InductorAdaptor(CompilerInterface):
     from torch._inductor.codecache import torch_key
     torch_factors = torch_key()
     factors.append(torch_factors)
+    return factors
+
+
+class InductorStandaloneAdaptor(CompilerInterface):
+    """
+    The adaptor for the Inductor compiler.
+    Requires PyTorch 2.8+.
+    This is not on by default yet, but we plan to turn it on by default for
+    PyTorch 2.8.
+
+    Use VLLM_TEST_STANDALONE_COMPILE to toggle this on or off.
+    """
+    name = "inductor_standalone"
+
+    def compute_hash(self, vllm_config: VllmConfig) -> str:
+        factors = get_inductor_factors()
+        hash_str = hashlib.md5(str(factors).encode(),
+                               usedforsecurity=False).hexdigest()[:10]
+        return hash_str
+
+    def initialize_cache(self, cache_dir: str, disable_cache: bool = False):
+        self.cache_dir = cache_dir
+
+    def compile(
+        self,
+        graph: fx.GraphModule,
+        example_inputs: List[Any],
+        compiler_config: Dict[str, Any],
+        runtime_shape: Optional[int] = None,
+        key: Optional[str] = None,
+    ) -> Tuple[Optional[Callable], Optional[Any]]:
+        current_config = {}
+        if compiler_config is not None:
+            current_config.update(compiler_config)
+        set_inductor_config(current_config, runtime_shape)
+
+        if isinstance(runtime_shape, int):
+            dynamic_shapes = "from_example_inputs"
+        else:
+            dynamic_shapes = "from_tracing_context"
+
+        from torch._inductor import standalone_compile
+        with pass_context(runtime_shape):
+            compiled_graph = standalone_compile(
+                graph,
+                example_inputs,
+                dynamic_shapes=dynamic_shapes,
+                options={"config_patches": current_config})
+
+        # Save the compiled artifact to disk in the specified path
+        assert key is not None
+        path = os.path.join(self.cache_dir, key)
+        compiled_graph.save(path=path, format="unpacked")
+        return compiled_graph, (key, path)
+
+    def load(self,
+             handle: Any,
+             graph: fx.GraphModule,
+             example_inputs: List[Any],
+             graph_index: int,
+             runtime_shape: Optional[int] = None) -> Callable:
+        assert isinstance(handle, tuple)
+        assert isinstance(handle[0], str)
+        assert isinstance(handle[1], str)
+        path = handle[1]
+        inductor_compiled_graph = torch._inductor.CompiledArtifact.load(
+            path=path, format="unpacked")
+        from torch._inductor.compile_fx import graph_returns_tuple
+        returns_tuple = graph_returns_tuple(graph)
+
+        def compiled_graph_wrapper(*args):
+            graph_output = inductor_compiled_graph(*args)
+            # unpack the tuple if needed
+            # TODO(rzou): the implication is that we're not
+            # reading the python bytecode correctly in vLLM?
+            if returns_tuple:
+                return graph_output
+            else:
+                return graph_output[0]
+
+        return compiled_graph_wrapper
+
+
+class InductorAdaptor(CompilerInterface):
+    """
+    The adaptor for the Inductor compiler, version 2.5, 2.6, 2.7.
+    """
+    name = "inductor"
+
+    def compute_hash(self, vllm_config: VllmConfig) -> str:
+        factors = get_inductor_factors()
         hash_str = hashlib.md5(str(factors).encode(),
                                usedforsecurity=False).hexdigest()[:10]
         return hash_str
@@ -168,23 +258,19 @@ class InductorAdaptor(CompilerInterface):
         graph: fx.GraphModule,
         example_inputs: List[Any],
         compiler_config: Dict[str, Any],
-        runtime_shape: Optional[int] = None
+        runtime_shape: Optional[int] = None,
+        key: Optional[str] = None,
     ) -> Tuple[Optional[Callable], Optional[Any]]:
-        current_config = {}
         from torch._inductor.compile_fx import compile_fx
+        current_config = {}
+        if compiler_config is not None:
+            current_config.update(compiler_config)
 
         # disable remote cache
         current_config["fx_graph_cache"] = True
         current_config["fx_graph_remote_cache"] = False
 
-        if compiler_config is not None:
-            current_config.update(compiler_config)
-
-        if isinstance(runtime_shape, int):
-            # for a specific batchsize, tuning triton kernel parameters
-            # can be beneficial
-            current_config["max_autotune"] = True
-            current_config["coordinate_descent_tuning"] = True
+        set_inductor_config(current_config, runtime_shape)
 
         # inductor can inplace modify the graph, so we need to copy it
         # see https://github.com/pytorch/pytorch/issues/138980
@@ -422,6 +508,14 @@ class InductorAdaptor(CompilerInterface):
             return contextlib.nullcontext()
 
 
+def set_inductor_config(config, runtime_shape):
+    if isinstance(runtime_shape, int):
+        # for a specific batchsize, tuning triton kernel parameters
+        # can be beneficial
+        config["max_autotune"] = True
+        config["coordinate_descent_tuning"] = True
+
+
 class EagerAdaptor(CompilerInterface):
     name = "eager"
 
@@ -430,7 +524,8 @@ class EagerAdaptor(CompilerInterface):
         graph: fx.GraphModule,
         example_inputs: List[Any],
         compiler_config: Dict[str, Any],
-        runtime_shape: Optional[int] = None
+        runtime_shape: Optional[int] = None,
+        key: Optional[str] = None,
     ) -> Tuple[Optional[Callable], Optional[Any]]:
         # we don't need to compile the graph, just return the graph itself.
         # It does not support caching, return None for the handle.

vllm/envs.py

@@ -263,6 +263,10 @@ environment_variables: dict[str, Callable[[], Any]] = {
     lambda: bool(
         os.environ.get("VLLM_TEST_DYNAMO_FULLGRAPH_CAPTURE", "1") != "0"),
 
+    # Internal flag to enable/disable Inductor standalone compile
+    "VLLM_TEST_STANDALONE_COMPILE":
+    lambda: os.environ.get("VLLM_TEST_STANDALONE_COMPILE", "0") != "0",
+
     # local rank of the process in the distributed setting, used to determine
     # the GPU device id
     "LOCAL_RANK":
@@ -805,6 +809,7 @@ def compute_hash() -> str:
         "VLLM_USE_TRITON_AWQ",
         "VLLM_DP_RANK",
         "VLLM_DP_SIZE",
+        "VLLM_TEST_STANDALONE_COMPILE",
     ]
     for key in environment_variables_to_hash:
         if key in environment_variables: