vllm/tests/v1/tpu/test_sampler.py
Hyesoo Yang 47195057e9
[V1][TPU] Speed up top-k on TPU by using torch.topk (#15242)
Signed-off-by: Hyesoo Yang <hyeygit@gmail.com>
2025-03-20 19:19:40 -07:00

96 lines
3.4 KiB
Python

# SPDX-License-Identifier: Apache-2.0
import tempfile
from time import time
import pytest
from vllm import LLM, envs
from vllm.platforms import current_platform
from vllm.sampling_params import SamplingParams
if not envs.VLLM_USE_V1:
pytest.skip(
"Skipping V1 tests. Rerun with `VLLM_USE_V1=1` to test.",
allow_module_level=True,
)
@pytest.mark.parametrize("model_name", ["D4nt3/Qwen2.5-two-layers"])
@pytest.mark.skipif(not current_platform.is_tpu(),
reason="This test needs a TPU")
def test_sampler_compilation(model_name: str, monkeypatch):
"""
Check that no recompilation happens despite changing sampling parameters.
We can't read XLA metrics from the engine process, hence we measure time.
"""
with tempfile.TemporaryDirectory() as temp_dir:
monkeypatch.setenv("VLLM_XLA_CACHE_PATH", temp_dir)
# Compiling model init may still take some time, enforce_eager to skip.
llm = LLM(model_name,
enforce_eager=True,
max_num_seqs=16,
max_model_len=1024,
gpu_memory_utilization=0.5)
prompts = [
"A robot may not injure a human being",
"It is only with the heart that one can see rightly;",
]
# First inference should be slow
sampling_params = SamplingParams(
temperature=0.7,
# top_p=0.6, # TODO too slow!
top_k=10,
min_p=0.2,
max_tokens=16)
s = time()
_ = llm.generate(prompts, sampling_params)
run1 = time() - s
# Second request with different params, but for which we
# compiled for in previous eager iteration.
sampling_params = SamplingParams(temperature=0.1,
top_k=12,
min_p=0.8,
max_tokens=24)
s = time()
_ = llm.generate(prompts, sampling_params)
run2 = time() - s
# Much faster after compiling
assert run1 * 0.1 > run2
print("TIMES", run1, run2)
# Third request with min_p set to "None". It will not trigger
# recompilation as a default 0 value will be used.
sampling_params = SamplingParams(max_tokens=24, temperature=0.0)
s = time()
_ = llm.generate(prompts, sampling_params)
run3 = time() - s
assert run1 * 0.1 > run3
print("TIMES", run1, run3)
@pytest.mark.parametrize("model_name", ["Qwen/Qwen2.5-1.5B-Instruct"])
@pytest.mark.skipif(not current_platform.is_tpu(),
reason="This test needs a TPU")
def test_sampler_different(model_name: str):
"""
Test significantly different sampling params to assert the model produces
different results.
"""
llm = LLM(
model_name,
enforce_eager=True,
max_num_seqs=1,
max_model_len=64,
# TODO: setting to 0.5 or it will go OOM
gpu_memory_utilization=0.5)
prompts = [
"Write a short story about a robot that dreams for the first time."
]
sampling_params = SamplingParams(temperature=0.9, min_p=0.2, max_tokens=64)
output = llm.generate(prompts, sampling_params)
sampling_params = SamplingParams(temperature=0.1, min_p=0.8, max_tokens=64)
output2 = llm.generate(prompts, sampling_params)
assert output[0].outputs[0].text != output2[0].outputs[0].text