[Test] Rework e2e async scheduling tests (#28744)

Signed-off-by: Nick Hill <nhill@redhat.com>

tests/v1/e2e/test_async_scheduling.py

 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+from itertools import repeat
 from typing import Any
 
 import pytest
@@ -8,126 +9,291 @@ import torch._dynamo.config as dynamo_config
 from vllm import SamplingParams
 from vllm.logprobs import Logprob
 from vllm.sampling_params import StructuredOutputsParams
+from vllm.v1.metrics.reader import Metric
 
 from ...conftest import VllmRunner
 from ...models.utils import check_outputs_equal
 
 MODEL = "Qwen/Qwen3-0.6B"
+MTP_MODEL = "XiaomiMiMo/MiMo-7B-Base"
 
 
-@dynamo_config.patch(cache_size_limit=16)
-def test_preempt_and_async_scheduling_e2e(
-    sample_json_schema, monkeypatch: pytest.MonkeyPatch
-):
-    """Test consistency of combos of async scheduling, preemption,
-    uni/multiproc executor, and various sampling parameters
-    including structured outputs."""
+first_prompt = (
+    "The following numbers of the sequence "
+    + ", ".join(str(i) for i in range(10))
+    + " are:"
+)
+example_prompts = [first_prompt, "In one word, the capital of France is "] + [
+    f"Tell me about the number {i}: " for i in range(32)
+]
 
-    first_prompt = (
-        "The following numbers of the sequence "
-        + ", ".join(str(i) for i in range(10))
-        + " are:"
-    )
-    example_prompts = [first_prompt, "In one word, the capital of France is "] + [
-        f"Tell me about the number {i}: " for i in range(32)
-    ]
+default_params = dict(
+    temperature=0.0,  # greedy
+    max_tokens=20,
+)
 
-    sampling_param_tests: list[dict[str, Any]] = [
+
+def test_without_spec_decoding(
+    sample_json_schema,
+    monkeypatch: pytest.MonkeyPatch,
+):
+    """Test consistency of combos of async scheduling, preemption,
+    uni/multiproc executor, prefill chunking."""
+    struct_outputs = StructuredOutputsParams(json=sample_json_schema)
+    test_sampling_params: list[dict[str, Any]] = [
         dict(),
         # dict(min_tokens=20),
         dict(presence_penalty=-1.0),
         dict(bad_words=["the", " the"]),
         dict(logprobs=2),
         dict(logprobs=2, presence_penalty=-1.0),
-        dict(structured_outputs=StructuredOutputsParams(json=sample_json_schema)),
+        dict(structured_outputs=struct_outputs),
         dict(
-            structured_outputs=StructuredOutputsParams(json=sample_json_schema),
+            structured_outputs=struct_outputs,
             logprobs=2,
             presence_penalty=-1.0,
         ),
     ]
 
-    default_params = dict(
-        temperature=0.0,  # greedy
-        max_tokens=20,
+    # test_preemption, executor, async_scheduling,
+    # spec_config, test_prefill_chunking
+    test_configs = [
+        (False, "mp", False, None, False),
+        (True, "mp", False, None, True),
+        (False, "mp", True, None, False),
+        (False, "uni", True, None, False),
+        (True, "mp", True, None, False),
+        (True, "uni", True, None, False),
+        (False, "mp", True, None, True),
+        # Async scheduling + preemption + chunked prefill needs to be fixed (WIP)
+        # (True, "mp", True, None, True),
+        # (True, "uni", True, None, True),
+    ]
+
+    run_tests(
+        monkeypatch,
+        MODEL,
+        test_configs,
+        test_sampling_params,
     )
 
+
+@pytest.mark.skip("MTP model too big to run in fp32 in CI")
+def test_with_spec_decoding(monkeypatch: pytest.MonkeyPatch):
+    """Test consistency and acceptance rates with some different combos of
+    preemption, executor, async scheduling, prefill chunking,
+    spec decoding model length.
+    """
+
+    spec_config = {
+        "method": "mtp",
+        "num_speculative_tokens": 2,
+    }
+    spec_config_short = spec_config | {"max_model_len": 50}
+
+    # test_preemption, executor, async_scheduling,
+    # spec_config, test_prefill_chunking
+    test_configs = [
+        (False, "mp", False, None, False),
+        (False, "mp", False, spec_config, False),
+        (True, "mp", False, spec_config, True),
+        (True, "uni", False, spec_config_short, True),
+        (False, "mp", True, spec_config, False),
+        (True, "mp", True, spec_config, False),
+        (False, "mp", True, spec_config_short, True),
+        (True, "uni", True, spec_config, False),
+        (True, "uni", True, spec_config_short, False),
+        # Async scheduling + preemption + chunked prefill needs to be fixed (WIP)
+        #  (True, "mp", True, spec_config, True),
+        #  (True, "uni", True, spec_config_short, True),
+    ]
+
+    run_tests(
+        monkeypatch,
+        MTP_MODEL,
+        test_configs,
+        [{}],
+    )
+
+
+@dynamo_config.patch(cache_size_limit=16)
+def run_tests(
+    monkeypatch: pytest.MonkeyPatch,
+    model: str,
+    test_configs: list[tuple],
+    test_sampling_params: list[dict[str, Any]],
+):
+    """Test consistency of combos of async scheduling, preemption,
+    uni/multiproc executor with spec decoding."""
+
     with monkeypatch.context() as m:
+        # avoid precision errors
         m.setenv("VLLM_ATTENTION_BACKEND", "FLEX_ATTENTION")
         # m.setenv("VLLM_BATCH_INVARIANT", "1")
+        outputs: list[tuple[str, list, list]] = []
+        for n, (
+            test_preemption,
+            executor,
+            async_scheduling,
+            spec_config,
+            test_prefill_chunking,
+        ) in enumerate(test_configs, 1):
+            test_str = f"{n}/{len(test_configs)}"
+            test_results = run_test(
+                model,
+                test_str,
+                test_sampling_params,
+                test_preemption,
+                executor,
+                async_scheduling,
+                spec_config,
+                test_prefill_chunking=test_prefill_chunking,
+            )
+            outputs.append(test_results)
+
+    baseline_config, baseline_tests, _ = outputs[0]
+    _, _, baseline_acceptances = next(
+        (o for o in outputs if o[2] is not None), (None, None, None)
+    )
 
-        outputs: list[tuple[str, list]] = []
-        for test_preemption in [False, True]:
-            for executor in ["mp", "uni"]:
-                for async_scheduling in [False, True]:
-                    cache_arg: dict[str, Any] = (
-                        dict(num_gpu_blocks_override=32)
-                        if test_preemption
-                        else dict(gpu_memory_utilization=0.7)
-                    )
-                    test_config = (
-                        f"executor={executor}, preemption={test_preemption},"
-                        f" async_sched={async_scheduling}"
-                    )
-                    print("-" * 80)
-                    print(f"---- TESTING: {test_config}")
-                    print("-" * 80)
-                    with VllmRunner(
-                        MODEL,
-                        max_model_len=512,
-                        enforce_eager=True,
-                        async_scheduling=async_scheduling,
-                        distributed_executor_backend=executor,
-                        dtype="float32",  # avoid precision errors
-                        **cache_arg,
-                    ) as vllm_model:
-                        results = []
-                        for override_params in sampling_param_tests:
-                            print(f"----------- RUNNING PARAMS: {override_params}")
-                            results.append(
-                                vllm_model.generate(
-                                    example_prompts,
-                                    sampling_params=SamplingParams(
-                                        **default_params, **override_params
-                                    ),
-                                    return_logprobs=True,
-                                )
-                            )
-
-                        if not outputs:
-                            # First check that the different parameter configs
-                            # actually result in different output.
-                            for (other_test_outs, other_test_logprobs), params in zip(
-                                results[1:], sampling_param_tests[1:]
-                            ):
-                                with pytest.raises(AssertionError):
-                                    check_outputs_equal(
-                                        outputs_0_lst=results[0][0],
-                                        outputs_1_lst=other_test_outs,
-                                        name_0=f"baseline params={params}",
-                                        name_1=f"other params={params}",
-                                    )
-                                    assert _all_logprobs_match(
-                                        results[0][1], other_test_logprobs
-                                    )
-
-                        outputs.append((test_config, results))
-
-    baseline_config, baseline_tests = outputs[0]
-
-    for test_config, test_outputs in outputs[1:]:
-        for (base_outs, base_logprobs), (test_outs, test_logprobs), params in zip(
-            baseline_tests, test_outputs, sampling_param_tests
+    print(f"BASELINE: config=[{baseline_config}], accept_rates={baseline_acceptances}")
+
+    failure = None
+    for test_config, test_outputs, test_acceptance_rates in outputs[1:]:
+        for (base_outs, base_logprobs), base_acceptance_rate, (
+            test_outs,
+            test_logprobs,
+        ), test_acceptance_rate, params in zip(
+            baseline_tests,
+            baseline_acceptances or repeat(None),
+            test_outputs,
+            test_acceptance_rates or repeat(None),
+            test_sampling_params,
         ):
-            check_outputs_equal(
-                outputs_0_lst=base_outs,
-                outputs_1_lst=test_outs,
-                name_0=f"baseline=[{baseline_config}], params={params}",
-                name_1=f"config=[{test_config}], params={params}",
+            try:
+                check_outputs_equal(
+                    outputs_0_lst=base_outs,
+                    outputs_1_lst=test_outs,
+                    name_0=f"baseline=[{baseline_config}], params={params}",
+                    name_1=f"config=[{test_config}], params={params}",
+                )
+                assert _all_logprobs_match(base_logprobs, test_logprobs)
+
+                if (
+                    base_acceptance_rate is not None
+                    and test_acceptance_rate is not None
+                ):
+                    if "spec_mml=None" in test_config:
+                        # because the acceptance rate can vary, we use a looser
+                        # tolerance here.
+                        assert (
+                            pytest.approx(test_acceptance_rate, rel=5e-2)
+                            == base_acceptance_rate
+                        )
+                    else:
+                        # Currently the reported acceptance rate is expected to be
+                        # lower when we skip drafting altogether.
+                        assert test_acceptance_rate > 0.05
+                print(
+                    f"PASSED: config=[{test_config}], params={params}"
+                    f" accept_rate={test_acceptance_rate}"
+                )
+            except AssertionError as e:
+                print(
+                    f"FAILED: config=[{test_config}], params={params}"
+                    f" accept_rate={test_acceptance_rate}"
+                )
+                if failure is None:
+                    failure = e
+
+    if failure is not None:
+        raise failure
+
+
+def run_test(
+    model: str,
+    test_str: str,
+    sampling_param_tests: list[dict[str, Any]],
+    test_preemption: bool,
+    executor: str,
+    async_scheduling: bool,
+    spec_config: dict[str, Any] | None,
+    test_prefill_chunking: bool,
+):
+    spec_decoding = spec_config is not None
+    cache_arg: dict[str, Any] = (
+        dict(num_gpu_blocks_override=32)
+        if test_preemption
+        else dict(gpu_memory_utilization=0.9)
+    )
+    spec_mml = (spec_config or {}).get("max_model_len")
+    test_config = (
+        f"executor={executor}, preemption={test_preemption}, "
+        f"async_sched={async_scheduling}, "
+        f"chunk_prefill={test_prefill_chunking}, "
+        f"spec_decoding={spec_decoding}, spec_mml={spec_mml}"
+    )
+    print("-" * 80)
+    print(f"---- TESTING {test_str}: {test_config}")
+    print("-" * 80)
+    with VllmRunner(
+        model,
+        max_model_len=512,
+        enable_chunked_prefill=test_prefill_chunking,
+        max_num_batched_tokens=48 if test_prefill_chunking else None,
+        # enforce_eager=True,
+        async_scheduling=async_scheduling,
+        distributed_executor_backend=executor,
+        dtype="float32",  # avoid precision errors
+        speculative_config=spec_config,
+        disable_log_stats=False,
+        **cache_arg,
+    ) as vllm_model:
+        results = []
+        acceptance_rates: list[float] | None = [] if spec_decoding else None
+        for override_params in sampling_param_tests:
+            metrics_before = vllm_model.llm.get_metrics()
+            print(f"----------- RUNNING PARAMS: {override_params}")
+            results.append(
+                vllm_model.generate(
+                    example_prompts,
+                    sampling_params=SamplingParams(
+                        **default_params,
+                        **override_params,
+                    ),
+                    return_logprobs=True,
+                )
             )
-            assert _all_logprobs_match(base_logprobs, test_logprobs)
+            metrics_after = vllm_model.llm.get_metrics()
+            if acceptance_rates is not None:
+                acceptance_rate = _get_acceptance_rate(metrics_before, metrics_after)
+                acceptance_rates.append(acceptance_rate)
+                print(f"ACCEPTANCE RATE {acceptance_rate}")
+
+            if test_preemption:
+                preemptions = _get_count(
+                    metrics_before,
+                    metrics_after,
+                    "vllm:num_preemptions",
+                )
+                assert preemptions > 0, "preemption test had no preemptions"
+
+    if len(results) > 1:
+        # First check that the different parameter configs
+        # actually result in different output.
+        for (other_test_outs, other_test_logprobs), params in zip(
+            results[1:], sampling_param_tests[1:]
+        ):
+            with pytest.raises(AssertionError):
+                check_outputs_equal(
+                    outputs_0_lst=results[0][0],
+                    outputs_1_lst=other_test_outs,
+                    name_0=f"baseline params={params}",
+                    name_1=f"other params={params}",
+                )
+                assert _all_logprobs_match(results[0][1], other_test_logprobs)
 
-            print(f"PASSED: config=[{test_config}], params={params}")
+    return test_config, results, acceptance_rates
 
 
 def _all_logprobs_match(req_a, req_b) -> bool:
@@ -149,3 +315,15 @@ def _logprobs_match(lps_a: dict[int, Logprob], lps_b: dict[int, Logprob]) -> boo
         and a.logprob == pytest.approx(b.logprob, rel=1e-3, abs=1e-6)
         for a, b in ((lps_a[x], lps_b[x]) for x in lps_a)
     )
+
+
+def _get_acceptance_rate(before: list[Metric], after: list[Metric]) -> float:
+    draft = _get_count(before, after, "vllm:spec_decode_num_draft_tokens")
+    accept = _get_count(before, after, "vllm:spec_decode_num_accepted_tokens")
+    return accept / draft if draft > 0 else 0.0
+
+
+def _get_count(before: list[Metric], after: list[Metric], name: str) -> int:
+    before_val = next(m.value for m in before if m.name == name)
+    after_val = next(m.value for m in after if m.name == name)
+    return after_val - before_val