vllm/tests/v1/tpu/test_sampler.py

113 lines
4.2 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import random
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", ["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=False,
max_num_seqs=1,
max_model_len=512,
max_num_batched_tokens=256)
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
with pytest.raises(ValueError):
# Unsupported `seed` param.
sampling_params = SamplingParams(temperature=0.3, seed=42)
output2 = llm.generate(prompts, sampling_params)
# Batch-case with TopK/P
for B in [4, 16]:
p = prompts * B
sampling_params = [
SamplingParams(
temperature=0.1,
min_p=0.8,
max_tokens=64,
# Vary number of ks
top_k=random.randint(4, 12),
top_p=random.random()) for _ in range(B)
]
# Make sure first two reqs have the same K/P
sampling_params[0] = sampling_params[1]
output = llm.generate(p, sampling_params)
# There are natural numerical instabilities that make it difficult
# to have deterministic results over many tokens, tests the first ~20
# tokens match.
assert output[0].outputs[0].text[:20] == output[1].outputs[0].text[:20]
@pytest.mark.parametrize("model_name", ["Qwen/Qwen2.5-1.5B-Instruct"])
# TODO TPU will appear busy if we fan-out test params here
@pytest.mark.parametrize("n_prompts", [1])
@pytest.mark.skipif(not current_platform.is_tpu(),
reason="This test needs a TPU")
def test_logprobs(model_name: str, n_prompts: int):
"""
Request top logprobs with different sampling settings and check
that results contains the requested number, ordered ascendingly.
"""
def check_num_logprobs(logprobs, expected_num: int):
for step in logprobs:
prev_logp = 1.0
# order by rank
sorted_step = dict(
sorted(step.items(), key=lambda item: item[1].rank))
# Can contain the sampled token
assert len(step) == expected_num or len(step) == expected_num + 1
# Check results are ordered by prob value
for rankno, (tid, logp) in enumerate(sorted_step.items()):
assert logp.logprob <= prev_logp
prev_logp = logp.logprob
assert logp.rank == rankno + 1
llm = LLM(model_name,
enforce_eager=False,
max_num_seqs=1,
max_model_len=128,
max_num_batched_tokens=128)
prompts = [
"Write a short story about a robot that dreams for the first time."
] * n_prompts
greedy_sampling_params = SamplingParams(temperature=0.0, max_tokens=64,\
logprobs=4)
regular_sampling_params = SamplingParams(temperature=0.4, max_tokens=64,\
logprobs=4)
topkp_sampling_params = SamplingParams(temperature=0.4, max_tokens=64,\
logprobs=4, top_k=12, top_p=0.5)
for sp in [greedy_sampling_params, regular_sampling_params, \
topkp_sampling_params]:
output = llm.generate(prompts, sp)
for o in output:
check_num_logprobs(o.outputs[0].logprobs, 4)