[Core] Allow full cudagraph with separate attention routines and orthogonal to compilation, add support for FA2 and FlashInfer

tests/compile/piecewise/test_full_cudagraph.py

@@ -3,7 +3,8 @@
 import contextlib
 import os
 import weakref
-from contextlib import ExitStack
+from dataclasses import dataclass
+from typing import Optional
 
 import pytest
 
@@ -32,69 +33,133 @@ def temporary_environ(env_vars):
                 os.environ[k] = v
 
 
-@pytest.fixture(scope="class")
-def llm_pair(request):
-    model = request.param
-
-    with temporary_environ({
-            "VLLM_USE_V1": "1",
-            "VLLM_FLASH_ATTN_VERSION": "3"
-    }):
-        full = LLM(
-            model=model,
-            gpu_memory_utilization=0.45,
-            trust_remote_code=True,
-            max_model_len=1024,
-            compilation_config=CompilationConfig(full_cuda_graph=True),
-        )
-        piecewise = LLM(
-            model=model,
-            gpu_memory_utilization=0.45,
-            trust_remote_code=True,
-            max_model_len=1024,
-            compilation_config=CompilationConfig(),
-        )
-
-    # PyTest caches the fixture values so we use weakref.proxy to enable GC
-    yield weakref.proxy(full), weakref.proxy(piecewise)
-    del full
-    del piecewise
-
-    wait_for_gpu_memory_to_clear(
-        devices=[0],
-        threshold_ratio=0.1,
-    )
-
-
-@pytest.fixture(scope="class")
-def cutlass_mla_llm_pair(request):
-    model = request.param
-
-    # force V1 engine and Cutlass MLA backend
-    with temporary_environ({
+@dataclass
+class BackendConfig:
+    name: str
+    env_vars: dict
+    comp_config: dict
+    specific_gpu_arch: Optional[tuple] = None
+
+
+# Define all backend configurations of full cudagraph to be tested
+backend_configs = {
+    # FA3 on Hopper
+    "FA3":
+    BackendConfig(name="FA3",
+                  env_vars={"VLLM_FLASH_ATTN_VERSION": "3"},
+                  comp_config={
+                      "cudagraph_mode": "FULL",
+                  },
+                  specific_gpu_arch=(9, 0)),
+    # FlashMLA on Hopper
+    "FlashMLA":
+    BackendConfig(name="FlashMLA",
+                  env_vars={
+                      "VLLM_ATTENTION_BACKEND": "FLASHMLA",
+                  },
+                  comp_config={
+                      "cudagraph_mode": "FULL_AND_PIECEWISE",
+                  },
+                  specific_gpu_arch=(9, 0)),
+    # Cutlass MLA on Blackwell
+    "CutlassMLA":
+    BackendConfig(
+        name="CutlassMLA",
+        env_vars={
             "VLLM_USE_V1": "1",
             "VLLM_ATTENTION_BACKEND": "CUTLASS_MLA",
             "FORCE_NUM_KV_SPLITS":
             "1",  # TODO: remove this when hang issue is fixed
-    }):
+        },
+        comp_config={
+            "cudagraph_mode": "FULL_AND_PIECEWISE",
+            "cudagraph_capture_sizes": [16, 32, 64, 128, 256, 512],
+        },
+        specific_gpu_arch=(10, 0)),
+    # FA2
+    "FA2":
+    BackendConfig(name="FA2",
+                  env_vars={"VLLM_FLASH_ATTN_VERSION": "2"},
+                  comp_config={
+                      "cudagraph_mode": "FULL",
+                  }),
+    # Triton Attention
+    "TritonAttn":
+    BackendConfig(name="TritonAttn",
+                  env_vars={"VLLM_ATTENTION_BACKEND": "TRITON_ATTN_VLLM_V1"},
+                  comp_config={
+                      "cudagraph_mode": "FULL",
+                  }),
+    # FlashInfer
+    "FlashInfer":
+    BackendConfig(name="FlashInfer",
+                  env_vars={"VLLM_ATTENTION_BACKEND": "FLASHINFER"},
+                  comp_config={
+                      "cudagraph_mode": "FULL_AND_PIECEWISE",
+                  }),
+}
+
+test_params_full_cudagraph = []
+
+# deepseek-ai/DeepSeek-V2-Lite with MLA
+MLA_backends = ["FlashMLA", "CutlassMLA"]
+for mla_backend in MLA_backends:
+    test_params_full_cudagraph.append(
+        pytest.param(
+            ("deepseek-ai/DeepSeek-V2-Lite", backend_configs[mla_backend])))
+
+# Qwen/Qwen2-1.5B-Instruct with other backends
+other_backend_configs = [
+    backend_configs[c] for c in backend_configs if c not in MLA_backends
+]
+for backend_config in other_backend_configs:
+    test_params_full_cudagraph.append(
+        pytest.param(("Qwen/Qwen2-1.5B-Instruct", backend_config)))
+
+
+@pytest.fixture(scope="class")
+def llm_pair(request):
+    model, backend_config = request.param
+
+    # Dynamically skip test if GPU capability is not met
+    if backend_config.specific_gpu_arch and backend_config.specific_gpu_arch\
+        != current_platform.get_device_capability():
+        if backend_config.specific_gpu_arch == (9, 0):
+            pytest.skip("Only Hopper GPUs support FA3 and FlashMLA")
+        elif backend_config.specific_gpu_arch == (10, 0):
+            pytest.skip("Only Blackwell GPUs support Cutlass MLA")
+
+    env_vars = {
+        "VLLM_USE_V1": "1",
+        # Force native sampler to avoid potential nondeterminism in FlashInfer
+        # when per-request generators are not used in V1.
+        "VLLM_USE_FLASHINFER_SAMPLER": "0",
+        **backend_config.env_vars,
+    }
+    with temporary_environ(env_vars):
         full = LLM(
             model=model,
-            gpu_memory_utilization=0.45,
+            gpu_memory_utilization=0.43,
             trust_remote_code=True,
             max_model_len=1024,
-            compilation_config=CompilationConfig(
-                full_cuda_graph=True,
-                cudagraph_capture_sizes=[16, 32, 64, 128, 256, 512],
-            ),
+            max_num_seqs=128,
+            compilation_config=\
+                CompilationConfig(**backend_config.comp_config),
+            generation_config="vllm",
+            seed=42,
         )
         piecewise = LLM(
             model=model,
-            gpu_memory_utilization=0.45,
+            gpu_memory_utilization=0.43,
             trust_remote_code=True,
             max_model_len=1024,
-            compilation_config=CompilationConfig(),
+            max_num_seqs=128,
+            compilation_config=CompilationConfig(cudagraph_mode="PIECEWISE"),
+            generation_config="vllm",
+            seed=42,
         )
 
+    # PyTest caches the fixture values so we use weakref.proxy to enable GC
     yield weakref.proxy(full), weakref.proxy(piecewise)
     del full
     del piecewise
@@ -105,51 +170,7 @@ def cutlass_mla_llm_pair(request):
     )
 
 
-@pytest.mark.parametrize(
-    "cutlass_mla_llm_pair",
-    [
-        # use an MLA model
-        "deepseek-ai/DeepSeek-V2-Lite",
-    ],
-    indirect=True)
-@pytest.mark.skipif(current_platform.get_device_capability() != (10, 0),
-                    reason="Only Blackwell GPUs support Cutlass MLA")
-class TestFullCUDAGraphCutlassMLA:
-    """
-    Validate full CUDA Graph with Cutlass MLA (decode-only capture).
-    """
-
-    @pytest.mark.parametrize(("batch_size", "max_tokens"), [
-        (8, 8),
-    ])
-    def test_full_cudagraph_sm100_cutlass_mla(
-            self, batch_size, max_tokens, cutlass_mla_llm_pair: tuple[LLM,
-                                                                      LLM]):
-        piecewise_llm, full_cudagraph_llm = cutlass_mla_llm_pair
-
-        prompts = ["Hello, my name is"] * batch_size
-        sampling_params = SamplingParams(temperature=0.0,
-                                         max_tokens=max_tokens,
-                                         top_p=0.95)
-
-        piecewise_responses = piecewise_llm.generate(prompts, sampling_params)
-        full_responses = full_cudagraph_llm.generate(prompts, sampling_params)
-
-        for piecewise_res, full_res in zip(piecewise_responses,
-                                           full_responses):
-            assert piecewise_res.outputs[0].text == full_res.outputs[0].text
-
-
-@pytest.mark.parametrize(
-    "llm_pair",
-    [
-        # Model names for the llm_pair fixture
-        "deepseek-ai/DeepSeek-V2-Lite",
-        "Qwen/Qwen2-1.5B-Instruct"
-    ],
-    indirect=True)
-@pytest.mark.skipif(current_platform.get_device_capability() != (9, 0),
-                    reason="Only Hopper GPUs support FA3 and FlashMLA")
+@pytest.mark.parametrize("llm_pair", test_params_full_cudagraph, indirect=True)
 class TestFullCUDAGraph:
     """
     Use a class such that an llm pair is constructed once for all
@@ -178,55 +199,31 @@ def test_full_cudagraph(self, batch_size, max_tokens,
         full cudagraph compilation works for padded cases too.
         """
 
-        piecewise_llm, full_cudagraph_llm = llm_pair
+        full_cudagraph_llm, piecewise_llm = llm_pair
 
-        prompts = ["Hello, my name is"] * batch_size
+        prompts = ["the quick brown fox"] * batch_size
+        # Use purely greedy decoding to avoid top-p truncation sensitivity
+        # that can amplify tiny numeric differences across runtimes.
         sampling_params = SamplingParams(temperature=0.0,
                                          max_tokens=max_tokens,
-                                         top_p=0.95)
+                                         top_p=1.0)
 
         piecewise_responses = piecewise_llm.generate(prompts, sampling_params)
         full_responses = full_cudagraph_llm.generate(prompts, sampling_params)
 
         # Check that all responses are the same
         for piecewise_res, full_res in zip(piecewise_responses,
                                            full_responses):
-            assert piecewise_res.outputs[0].text == full_res.outputs[0].text
-
-
-@pytest.mark.parametrize(
-    "model, supported",
-    [
-        ("Qwen/Qwen2-1.5B-Instruct", True),
-        # MLA does not support capturing CUDA Graphs with size > max_num_seqs
-        ("deepseek-ai/DeepSeek-V2-Lite", False),
-    ])
-@pytest.mark.skipif(current_platform.get_device_capability() != (9, 0),
-                    reason="Only Hopper GPUs support FA3 and FlashMLA")
-def test_lower_max_num_seqs(model, supported):
-    with temporary_environ({
-            "VLLM_USE_V1": "1",
-            "VLLM_FLASH_ATTN_VERSION": "3"
-    }), ExitStack() as stack:
-        if not supported:
-            stack.enter_context(pytest.raises(RuntimeError))
-
-        llm = LLM(model=model,
-                  max_num_seqs=256,
-                  trust_remote_code=True,
-                  max_model_len=1024,
-                  compilation_config=CompilationConfig(
-                      full_cuda_graph=True,
-                      cudagraph_capture_sizes=[64, 256, 512]))
-        llm.generate(["Hello, my name is"] * 10)
+            assert piecewise_res.outputs[0].text.lower() == \
+                full_res.outputs[0].text.lower()
 
 
 @pytest.mark.skipif(not current_platform.is_cuda(), reason="Skip if not cuda")
 def test_full_cudagraph_with_invalid_backend():
     with temporary_environ({
             "VLLM_USE_V1": "1",
-            "VLLM_FLASH_ATTN_VERSION":
-            "2"  #FA2 not supported with full_cuda_graph
+            "VLLM_ATTENTION_BACKEND": "FLEX_ATTENTION"
+            # Flex_Attention is not supported with full cuda graph
     }), pytest.raises(RuntimeError):
         LLM(model="Qwen/Qwen2-1.5B-Instruct",
-            compilation_config=CompilationConfig(full_cuda_graph=True))
+            compilation_config=CompilationConfig(cudagraph_mode="FULL"))

tests/compile/piecewise/test_simple.py

@@ -11,10 +11,10 @@
 
 from vllm.compilation.counter import compilation_counter
 from vllm.compilation.decorators import support_torch_compile
-from vllm.config import (CompilationConfig, CompilationLevel, VllmConfig,
-                         set_current_vllm_config)
+from vllm.config import (CompilationConfig, CompilationLevel, CUDAGraphMode,
+                         VllmConfig, set_current_vllm_config)
 from vllm.envs import VLLM_USE_V1
-from vllm.forward_context import set_forward_context
+from vllm.forward_context import BatchDescriptor, set_forward_context
 from vllm.utils import direct_register_custom_op
 
 global_counter = 0
@@ -101,16 +101,33 @@ def test_simple_piecewise_compile(use_inductor):
             num_backend_compilations=3,  # num_piecewise_capturable_graphs_seen
             num_cudagraph_captured=
             6,  # num_cudagraph_sizes * num_piecewise_capturable_graphs_seen
-    ), set_forward_context({}, vllm_config=vllm_config):
-
+    ), set_forward_context(None,
+                           vllm_config=vllm_config):  # background context
+        # warm up with background context
         model(inputs)
 
-        model(torch.randn(2).cuda())
-        model(torch.randn(1).cuda())
+        # capturing/replaying should under context of cudagraph dispatching
+        with set_forward_context(
+                None,
+                vllm_config=vllm_config,
+                cudagraph_runtime_mode=CUDAGraphMode.PIECEWISE,
+                batch_descriptor=BatchDescriptor(num_tokens=2, )):
+            model(torch.randn(2).cuda())
+        with set_forward_context(
+                None,
+                vllm_config=vllm_config,
+                cudagraph_runtime_mode=CUDAGraphMode.PIECEWISE,
+                batch_descriptor=BatchDescriptor(num_tokens=1, )):
+            model(torch.randn(1).cuda())
 
         input = torch.zeros(2).cuda()
         global global_counter
         global_counter = 0
-        output = model(input)
+        with set_forward_context(
+                None,
+                vllm_config=vllm_config,
+                cudagraph_runtime_mode=CUDAGraphMode.PIECEWISE,
+                batch_descriptor=BatchDescriptor(num_tokens=2, )):
+            output = model(input)
         assert global_counter == 2
         assert torch.allclose(output.cpu(), torch.tensor([3., 1.]))