vllm/tests/prefix_caching/test_prefix_caching.py

88 lines
2.6 KiB
Python

"""Compare the with and without prefix caching.
Run `pytest tests/prefix_caching/test_prefix_caching.py`.
"""
import pytest
from tests.kernels.utils import override_backend_env_variable
from vllm import SamplingParams, TokensPrompt
from ..models.utils import check_outputs_equal
MODELS = [
"facebook/opt-125m",
]
UNSTABLE_PROMPT_SEQUENCE = [
([0] * 588) + ([1] * 1332) + ([2] * 30) + ([3] * 1),
([0] * 588) + ([1] * 1332) + ([4] * 3) + ([5] * 50),
([0] * 588) + ([1] * 1332) + ([2] * 30) + ([6] * 95),
([0] * 588) + ([1] * 1332) + ([4] * 3) + ([7] * 174),
([0] * 588) + ([8] * 1539),
]
@pytest.mark.parametrize("model", MODELS)
@pytest.mark.parametrize("backend", ["FLASH_ATTN", "FLASHINFER", "XFORMERS"])
@pytest.mark.parametrize("dtype", ["half"])
@pytest.mark.parametrize("max_tokens", [5])
@pytest.mark.parametrize("cached_position", [0, 1])
def test_mixed_requests(
hf_runner,
vllm_runner,
example_prompts,
model: str,
backend: str,
dtype: str,
max_tokens: int,
cached_position: int,
monkeypatch,
) -> None:
"""
Test the case when some sequences have the prefix cache hit
and the others don't. The cached position determines where
the sequence is at among the batch of prefills.
"""
override_backend_env_variable(monkeypatch, backend)
with hf_runner(model, dtype=dtype) as hf_model:
hf_outputs = hf_model.generate_greedy(example_prompts, max_tokens)
cached_prompt = example_prompts[cached_position]
with vllm_runner(
model,
dtype=dtype,
enable_prefix_caching=True,
) as vllm_model:
# Run the first prompt so the cache is populated
vllm_outputs = vllm_model.generate_greedy([cached_prompt], max_tokens)
# Run all the promopts
vllm_outputs = vllm_model.generate_greedy(example_prompts, max_tokens)
check_outputs_equal(
outputs_0_lst=hf_outputs,
outputs_1_lst=vllm_outputs,
name_0="hf",
name_1="vllm",
)
@pytest.mark.parametrize("backend", ["FLASH_ATTN", "FLASHINFER", "XFORMERS"])
def test_unstable_prompt_sequence(
vllm_runner,
backend: str,
monkeypatch,
) -> None:
override_backend_env_variable(monkeypatch, backend)
with vllm_runner(
"Qwen/Qwen2.5-0.5B-Instruct",
enable_chunked_prefill=True,
enable_prefix_caching=True,
max_model_len=4096,
) as vllm_model:
for prompt in UNSTABLE_PROMPT_SEQUENCE:
vllm_model.generate(TokensPrompt(prompt_token_ids=prompt),
SamplingParams(max_tokens=1))