[Speculative decoding 6/9] Integrate speculative decoding with LLMEngine (#3894)

Author: cadedaniel

tests/core/block/e2e/test_correctness.py

@@ -230,6 +230,76 @@ def test_lookahead_greedy_equality_with_preemption(baseline_llm_generator,
     assert baseline_token_ids == test_token_ids
 
 
+@pytest.mark.parametrize(
+    "common_llm_kwargs",
+    [
+        {
+            # Use a small model for a fast test.
+            "model": "facebook/opt-125m",
+
+            # skip cuda graph creation for fast test.
+            "enforce_eager": True,
+            "enable_chunked_prefill": True,
+            "max_num_batched_tokens": 2,
+            "max_num_seqs": 2,
+        },
+    ])
+@pytest.mark.parametrize("per_test_common_llm_kwargs", [{}])
+@pytest.mark.parametrize("baseline_llm_kwargs", [
+    {
+        "use_v2_block_manager": False,
+    },
+])
+@pytest.mark.parametrize("test_llm_kwargs", [
+    {
+        "use_v2_block_manager": True,
+        "num_lookahead_slots": 0,
+    },
+    {
+        "use_v2_block_manager": True,
+        "num_lookahead_slots": 5,
+    },
+])
+@pytest.mark.parametrize("batch_size", [4])
+@pytest.mark.parametrize("seed", [1])
+def test_chunked_prefill_block_manager_v2(baseline_llm_generator,
+                                          test_llm_generator, batch_size):
+    """Verify that chunked prefill works with BlockManagerV2, with and without
+    lookahead scheduling.
+    """
+    output_len = 32
+    temperature = 0.0
+
+    prompts = [
+        "Hello, my name is",
+        "The president of the United States is",
+        "The capital of France is",
+        "The future of AI is",
+    ]
+
+    prompts = [prompt for prompt, _ in zip(cycle(prompts), range(batch_size))]
+
+    sampling_params = SamplingParams(
+        max_tokens=output_len,
+        ignore_eos=True,
+        temperature=temperature,
+    )
+
+    print('Getting token ids with BlockManagerV1')
+    baseline_token_ids = get_token_ids_from_llm_generator(
+        baseline_llm_generator, prompts, sampling_params)
+
+    print('Getting token ids with BlockManagerV2')
+    test_token_ids = get_token_ids_from_llm_generator(test_llm_generator,
+                                                      prompts, sampling_params)
+
+    for expected_token_ids, actual_token_ids in zip(baseline_token_ids,
+                                                    test_token_ids):
+        assert expected_token_ids == actual_token_ids
+
+    assert baseline_token_ids == test_token_ids
+
+
 def get_token_ids_from_llm_generator(llm_generator, prompts, sampling_params):
     for llm in llm_generator:
         outputs = llm.generate(prompts, sampling_params, use_tqdm=True)

tests/core/utils.py

@@ -1,5 +1,5 @@
 import time
-from typing import Optional, Tuple
+from typing import Iterable, Optional, Tuple
 
 from vllm import SamplingParams
 from vllm.lora.request import LoRARequest
@@ -31,14 +31,17 @@ def create_dummy_prompt(
 
 
 def create_seq_group(
-    seq_prompt_len=1024,
-    seq_output_lens=(128, ),
-    request_id='0',
-    seq_id_start=0,
-) -> SequenceGroup:
+        seq_prompt_len: int = 1024,
+        seq_output_lens: Iterable[int] = (128, ),
+        request_id: str = '0',
+        seq_id_start: int = 0,
+        sampling_params: Optional[SamplingParams] = None) -> SequenceGroup:
 
     assert len(seq_output_lens) > 0
 
+    if sampling_params is None:
+        sampling_params = SamplingParams()
+
     prompt_token_ids = [0] * seq_prompt_len
 
     seqs = []
@@ -60,7 +63,7 @@ def create_seq_group(
     seq_group = SequenceGroup(
         request_id=request_id,
         seqs=seqs,
-        sampling_params=SamplingParams(),
+        sampling_params=sampling_params,
         arrival_time=time.time(),
     )
 

tests/engine/output_processor/test_multi_step.py

@@ -0,0 +1,270 @@
+import random
+from unittest.mock import MagicMock
+
+import pytest
+from transformers import PreTrainedTokenizer
+
+from tests.core.utils import create_seq_group
+from vllm.core.scheduler import Scheduler
+from vllm.engine.output_processor.multi_step import MultiStepOutputProcessor
+from vllm.engine.output_processor.stop_checker import StopChecker
+from vllm.sampling_params import SamplingParams
+from vllm.sequence import (Logprob, SequenceGroupOutput, SequenceOutput,
+                           SequenceStatus)
+from vllm.transformers_utils.detokenizer import Detokenizer
+from vllm.utils import Counter
+
+
+@pytest.mark.parametrize("seq_output_len", [128])
+@pytest.mark.parametrize("num_new_tokens", [1, 12])
+@pytest.mark.skip_global_cleanup
+def test_appends_token_ids(num_new_tokens: int, seq_output_len: int):
+    """Verify multi-step decoding appends token ids correctly.
+
+    We append token ids and verify all the token ids were appended correctly.
+    Note that ignore_eos=True.
+    """
+    detokenizer = MagicMock(spec=Detokenizer)
+    scheduler = MagicMock(spec=Scheduler)
+    stop_checker = MagicMock(spec=StopChecker)
+    seq_counter = Counter()
+
+    output_processor = MultiStepOutputProcessor(
+        detokenizer=detokenizer,
+        scheduler=scheduler,
+        seq_counter=seq_counter,
+        get_tokenizer_for_seq=lambda _: mock_tokenizer(),
+        stop_checker=stop_checker,
+    )
+
+    seq_group = create_seq_group(
+        seq_prompt_len=1024,
+        seq_output_lens=[seq_output_len],
+        sampling_params=SamplingParams(max_tokens=seq_output_len +
+                                       num_new_tokens,
+                                       ignore_eos=True),
+    )
+
+    seq = seq_group.get_seqs()[0]
+    seq.status = SequenceStatus.RUNNING
+
+    new_token_ids = list(range(num_new_tokens))
+
+    outputs = [
+        SequenceGroupOutput(
+            samples=[
+                SequenceOutput(
+                    parent_seq_id=seq.seq_id,
+                    output_token=output_token,
+                    logprobs={output_token: Logprob(0.0)},
+                )
+            ],
+            prompt_logprobs=None,
+        ) for output_token in new_token_ids
+    ]
+
+    assert seq.get_token_ids()[-len(new_token_ids):] != new_token_ids
+    output_processor.process_outputs(seq_group, outputs)
+    assert seq.get_token_ids()[-len(new_token_ids):] == new_token_ids
+
+
+@pytest.mark.parametrize("seq_prompt_len", [1024])
+@pytest.mark.parametrize("seq_output_len", [128])
+@pytest.mark.parametrize("num_new_tokens", [5, 6, 7, 8])
+@pytest.mark.parametrize("max_tokens", [128 + 3])
+@pytest.mark.skip_global_cleanup
+def test_respects_max_tokens(num_new_tokens: int, seq_prompt_len: int,
+                             seq_output_len: int, max_tokens: int):
+    """Verify tokens after max_tokens are dropped and not appended to the
+    sequence.
+    """
+    detokenizer = MagicMock(spec=Detokenizer)
+    scheduler = MagicMock(spec=Scheduler)
+    stop_checker = MagicMock(spec=StopChecker)
+    seq_counter = Counter()
+
+    output_processor = MultiStepOutputProcessor(
+        detokenizer=detokenizer,
+        scheduler=scheduler,
+        seq_counter=seq_counter,
+        get_tokenizer_for_seq=lambda _: mock_tokenizer(),
+        stop_checker=stop_checker,
+    )
+
+    seq_group = create_seq_group(
+        seq_prompt_len=seq_prompt_len,
+        seq_output_lens=[seq_output_len],
+        sampling_params=SamplingParams(max_tokens=max_tokens, ),
+    )
+
+    seq = seq_group.get_seqs()[0]
+    seq.status = SequenceStatus.RUNNING
+
+    new_token_ids = list(range(num_new_tokens))
+
+    outputs = [
+        SequenceGroupOutput(
+            samples=[
+                SequenceOutput(
+                    parent_seq_id=seq.seq_id,
+                    output_token=output_token,
+                    logprobs={output_token: Logprob(0.0)},
+                )
+            ],
+            prompt_logprobs=None,
+        ) for output_token in new_token_ids
+    ]
+
+    assert seq.get_len() == seq_prompt_len + seq_output_len
+    output_processor.process_outputs(seq_group, outputs)
+
+    # Expect the processed sequence to not go over max tokens in len.
+    assert seq.get_len() == seq_prompt_len + max_tokens
+
+    # Expect the correct tokens were appended.
+    expected_appended_tokens = new_token_ids[:max_tokens - seq_output_len]
+    assert seq.get_token_ids(
+    )[-len(expected_appended_tokens):] == expected_appended_tokens
+
+
+@pytest.mark.parametrize("seq_prompt_len", [1024])
+@pytest.mark.parametrize("seq_output_len", [128])
+@pytest.mark.parametrize("num_new_tokens", [12])
+@pytest.mark.parametrize("seed", list(range(6)))
+@pytest.mark.skip_global_cleanup
+def test_respects_eos_token_id(num_new_tokens: int, seq_prompt_len: int,
+                               seq_output_len: int, seed: int):
+    """Verify the eos token id is included in the sequence, but subsequent
+    tokens are dropped (not appended to sequence).
+    """
+    random.seed(seed)
+    detokenizer = MagicMock(spec=Detokenizer)
+    scheduler = MagicMock(spec=Scheduler)
+    stop_checker = MagicMock(spec=StopChecker)
+    seq_counter = Counter()
+
+    eos_token_id = 100
+
+    output_processor = MultiStepOutputProcessor(
+        detokenizer=detokenizer,
+        scheduler=scheduler,
+        seq_counter=seq_counter,
+        get_tokenizer_for_seq=lambda _: mock_tokenizer(eos_token_id),
+        stop_checker=stop_checker,
+    )
+
+    seq_group = create_seq_group(
+        seq_prompt_len=seq_prompt_len,
+        seq_output_lens=[seq_output_len],
+        sampling_params=SamplingParams(
+            # Ensure enough space.
+            max_tokens=seq_output_len + num_new_tokens, ),
+    )
+
+    seq = seq_group.get_seqs()[0]
+    seq.status = SequenceStatus.RUNNING
+
+    new_token_ids = list(range(num_new_tokens))
+    assert eos_token_id not in new_token_ids
+    eos_index = random.randint(0, len(new_token_ids) - 1)
+    new_token_ids[eos_index] = eos_token_id
+
+    outputs = [
+        SequenceGroupOutput(
+            samples=[
+                SequenceOutput(
+                    parent_seq_id=seq.seq_id,
+                    output_token=output_token,
+                    logprobs={output_token: Logprob(0.0)},
+                )
+            ],
+            prompt_logprobs=None,
+        ) for output_token in new_token_ids
+    ]
+
+    assert seq.get_len() == seq_prompt_len + seq_output_len
+    output_processor.process_outputs(seq_group, outputs)
+
+    # Expect the processed sequence to not go beyond provided eos.
+    assert seq.get_len() == seq_prompt_len + seq_output_len + (eos_index + 1)
+
+    # Expect the correct tokens were appended.
+    expected_appended_tokens = new_token_ids[:eos_index + 1]
+    assert seq.get_token_ids(
+    )[-len(expected_appended_tokens):] == expected_appended_tokens
+
+
+@pytest.mark.parametrize("seq_prompt_len", [1024])
+@pytest.mark.parametrize("seq_output_len", [128])
+@pytest.mark.parametrize("num_new_tokens", [12])
+@pytest.mark.parametrize("seed", list(range(6)))
+@pytest.mark.skip_global_cleanup
+def test_ignores_eos_token_id(num_new_tokens: int, seq_prompt_len: int,
+                              seq_output_len: int, seed: int):
+    """When sampling parameters dictate that we should ignore the eos token id,
+    ensure all token ids are appended even if the eos token id is emitted.
+    """
+    random.seed(seed)
+    detokenizer = MagicMock(spec=Detokenizer)
+    scheduler = MagicMock(spec=Scheduler)
+    stop_checker = MagicMock(spec=StopChecker)
+    seq_counter = Counter()
+
+    eos_token_id = 100
+
+    output_processor = MultiStepOutputProcessor(
+        detokenizer=detokenizer,
+        scheduler=scheduler,
+        seq_counter=seq_counter,
+        get_tokenizer_for_seq=lambda _: mock_tokenizer(eos_token_id),
+        stop_checker=stop_checker,
+    )
+
+    seq_group = create_seq_group(
+        seq_prompt_len=seq_prompt_len,
+        seq_output_lens=[seq_output_len],
+        sampling_params=SamplingParams(
+            # Ensure enough space.
+            max_tokens=seq_output_len + num_new_tokens,
+            ignore_eos=True,
+        ),
+    )
+
+    seq = seq_group.get_seqs()[0]
+    seq.status = SequenceStatus.RUNNING
+
+    new_token_ids = list(range(num_new_tokens))
+    assert eos_token_id not in new_token_ids
+    eos_index = random.randint(0, len(new_token_ids) - 1)
+    new_token_ids[eos_index] = eos_token_id
+
+    outputs = [
+        SequenceGroupOutput(
+            samples=[
+                SequenceOutput(
+                    parent_seq_id=seq.seq_id,
+                    output_token=output_token,
+                    logprobs={output_token: Logprob(0.0)},
+                )
+            ],
+            prompt_logprobs=None,
+        ) for output_token in new_token_ids
+    ]
+
+    assert seq.get_len() == seq_prompt_len + seq_output_len
+    output_processor.process_outputs(seq_group, outputs)
+
+    # Expect the processed sequence to go beyond eos.
+    assert seq.get_len() == seq_prompt_len + seq_output_len + num_new_tokens
+
+    # Expect the correct tokens were appended.
+    expected_appended_tokens = new_token_ids[:seq_output_len + num_new_tokens -
+                                             seq_output_len]
+    assert seq.get_token_ids(
+    )[-len(expected_appended_tokens):] == expected_appended_tokens
+
+
+def mock_tokenizer(eos_token_id=1000):
+    tokenizer = MagicMock(spec=PreTrainedTokenizer)
+    tokenizer.eos_token_id = eos_token_id
+    return tokenizer