vllm/tests/spec_decode/test_scorer.py
2025-03-02 17:34:51 -08:00

117 lines
5.0 KiB
Python

# SPDX-License-Identifier: Apache-2.0
import random
import pytest
import torch
from vllm.sequence import ExecuteModelRequest
from vllm.spec_decode.batch_expansion import BatchExpansionTop1Scorer
from vllm.spec_decode.interfaces import SpeculativeProposals, SpeculativeScores
from vllm.spec_decode.mqa_scorer import MQAScorer
from vllm.worker.worker import Worker
from .utils import create_batch, create_worker
def create_proposal(propose_lens: list[int], vocab_size: int,
device: str) -> SpeculativeProposals:
batch_size = len(propose_lens)
max_propose_len = max(propose_lens)
proposal_probs = torch.rand((batch_size, max_propose_len, vocab_size),
device=device)
proposal_token_ids = torch.full((batch_size, max_propose_len),
fill_value=-1,
device=device)
for i in range(batch_size):
proposal_token_ids[i][:propose_lens[i]] = torch.argmax(
proposal_probs[i][:propose_lens[i]], dim=-1)
propose_lens = torch.tensor(propose_lens, device=device)
return SpeculativeProposals(proposal_token_ids, proposal_probs,
propose_lens)
def assert_score_equal(score1: SpeculativeScores,
score2: SpeculativeScores) -> None:
assert torch.allclose(score1.probs, score2.probs)
assert torch.allclose(score1.logprobs, score2.logprobs)
assert torch.equal(
score1.token_ids,
score2.token_ids), f"{score1.token_ids}, {score2.token_ids}"
@pytest.mark.parametrize('model_name', ['facebook/opt-125m'])
@pytest.mark.parametrize('batch_size', [1, 2, 4, 8, 16])
@pytest.mark.parametrize('max_propose_len', [1, 3, 5])
@pytest.mark.parametrize('mixed_propose_len', [True])
@pytest.mark.parametrize('device', ['cuda'])
@pytest.mark.parametrize('prefill_chunking', [False, True])
def test_scorer(model_name: str, batch_size: int, max_propose_len: int,
mixed_propose_len: bool, device: str,
prefill_chunking: bool) -> None:
"""
Compare the batch expansion scorer and mqa scorer return the same score.
We test for both queries with the same propose length and different
propose length, as well as mixed prefill-decode batches.
"""
seed = 0
block_size = 32
num_gpu_blocks = 2048 // block_size
scorer_worker = create_worker(Worker, model_name, block_size,
num_gpu_blocks, seed)
scorer_worker.model_runner.disable_logprobs = True # accessed by mqa_scorer
scorer_worker.model_runner.model.sampler.include_gpu_probs_tensor = True
scorer_worker.model_runner.model.sampler.\
should_modify_greedy_probs_inplace = True
vocab_size = scorer_worker.vocab_size
if not mixed_propose_len:
propose_lens = [max_propose_len] * batch_size
else:
# There must be at least 1 decode request, otherwise
# we have nothing to score (`_run_no_spec`).
non_zero_cnt = random.randint(1, batch_size)
propose_lens = [max_propose_len
] * non_zero_cnt + [0] * (batch_size - non_zero_cnt)
random.shuffle(propose_lens)
seq_group_metadatalist, _, _ = create_batch(batch_size,
max_propose_len,
block_size=block_size,
num_gpu_blocks=num_gpu_blocks)
if mixed_propose_len and prefill_chunking and (n_prefills :=
batch_size - non_zero_cnt):
prefill, _, _ = create_batch(n_prefills,
None,
prefill_chunk_size=4,
block_size=block_size,
num_gpu_blocks=num_gpu_blocks,
seq_ids=list(
range(batch_size,
batch_size + n_prefills)))
# re-order to guarantee prefill|decode order
target_group_metadatalist = [
seq_group_metadatalist[i] for i, p in enumerate(propose_lens)
if p > 0
]
seq_group_metadatalist = prefill + target_group_metadatalist
propose_lens = [0] * n_prefills + [p for p in propose_lens if p > 0]
proposals = create_proposal(propose_lens, vocab_size, device)
requests = ExecuteModelRequest(seq_group_metadatalist,
num_lookahead_slots=max_propose_len)
batch_expansion_scorer = BatchExpansionTop1Scorer(scorer_worker, device,
vocab_size)
batch_expansion_score = batch_expansion_scorer.score_proposals(
requests, proposals)
mqa_scorer = MQAScorer(scorer_worker, device, vocab_size)
mqa_score = mqa_scorer.score_proposals(requests, proposals)
assert_score_equal(batch_expansion_score, mqa_score)