[Core] Sliding window for block manager v2 (#4545)

Co-authored-by: Ruth Evans <ruthevans@Ruths-MacBook-Pro.local>
This commit is contained in:
Michał Moskal
2024-05-27 19:07:07 -07:00
committed by GitHub
parent 890aa93d27
commit d4f3985907
12 changed files with 457 additions and 45 deletions

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@ -1,3 +1,5 @@
from typing import Callable, Iterable, Optional
import pytest
from vllm import LLM
@ -40,3 +42,27 @@ def create_llm_generator(common_llm_kwargs, per_test_common_llm_kwargs,
for llm in generator_inner():
yield llm
del llm
def get_text_from_llm_generator(llm_generator: Iterable[LLM],
prompts,
sampling_params,
llm_cb: Optional[Callable[[LLM],
None]] = None):
for llm in llm_generator:
if llm_cb:
llm_cb(llm)
outputs = llm.generate(prompts, sampling_params, use_tqdm=True)
text = [output.outputs[0].text for output in outputs]
del llm
return text
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)
token_ids = [output.outputs[0].token_ids for output in outputs]
del llm
return token_ids

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@ -4,6 +4,8 @@ import pytest
from vllm import SamplingParams
from .conftest import get_token_ids_from_llm_generator
@pytest.mark.parametrize(
"common_llm_kwargs",
@ -444,12 +446,3 @@ def test_auto_prefix_caching_with_preemption(baseline_llm_generator,
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)
token_ids = [output.outputs[0].token_ids for output in outputs]
del llm
return token_ids

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@ -0,0 +1,168 @@
import random
from typing import List
import pytest
from vllm import LLM, SamplingParams
from .conftest import get_text_from_llm_generator
# relatively small model with 4k sliding window
MODEL = "bigcode/starcoder2-3b"
BLOCK_SIZE = 16
@pytest.mark.parametrize(
"common_llm_kwargs",
[{
"model": MODEL,
# skip cuda graph creation for fast test.
"enforce_eager": True,
"block_size": BLOCK_SIZE,
# needed due to https://github.com/vllm-project/vllm/issues/1908#issuecomment-2101122008
"num_gpu_blocks_override": 100000 // BLOCK_SIZE,
}])
@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}])
@pytest.mark.parametrize("batch_size", [5])
@pytest.mark.parametrize("seed", [1])
def test_sliding_window_retrival(baseline_llm_generator, test_llm_generator,
batch_size, seed):
"""
The test does a bunch of assignments "x1 = 10\nx2 = 33\n..." and then
asks for value of one of them (which is outside the sliding window).
If we tell it upfront which we are going to be looking for, then
it answers correctly (mostly).
Additionally, we compare the results of the v1 and v2 managers.
"""
sampling_params = SamplingParams(
max_tokens=1024,
ignore_eos=True,
temperature=0.0,
)
prompts, answer, indices = prep_prompts(batch_size)
print('Getting token ids from block manager v1')
baseline_texts = get_text_from_llm_generator(baseline_llm_generator,
prompts,
sampling_params,
llm_cb=check_window(prompts))
check_answers(indices, answer, baseline_texts)
print('Getting token ids from block manager v2')
test_texts = get_text_from_llm_generator(test_llm_generator, prompts,
sampling_params)
check_answers(indices, answer, test_texts)
cmp = [
expected_text == actual_text
for expected_text, actual_text in zip(baseline_texts, test_texts)
]
print(cmp)
# make sure it's mostly OK; this is possibly because https://github.com/vllm-project/vllm/pull/4768
# however, https://github.com/vllm-project/vllm/issues/3385#issuecomment-1995924290
# states that xformers and flash_attn have different ideas about the window
# size anyways
assert sum(cmp) > 0.7 * len(cmp)
@pytest.mark.parametrize(
"common_llm_kwargs",
[{
"model": MODEL,
# skip cuda graph creation for fast test.
"enforce_eager": True,
"block_size": BLOCK_SIZE,
"num_gpu_blocks_override": 100000 // BLOCK_SIZE,
}])
@pytest.mark.parametrize("per_test_common_llm_kwargs", [{}])
@pytest.mark.parametrize("test_llm_kwargs", [{
"use_v2_block_manager": True,
"enable_chunked_prefill": True
}])
@pytest.mark.parametrize("batch_size", [5])
@pytest.mark.parametrize("seed", [1])
def test_sliding_window_chunked_prefill(test_llm_generator, batch_size, seed):
"""
This is similar to test_sliding_window_retrival, however, it doesn't
compare against the v1 block manager since v1 doesn't support
chunked prefill with sliding window.
The results with and without chunked prefill are not the same due to
numerical instabilities.
"""
sampling_params = SamplingParams(
max_tokens=10,
ignore_eos=True,
temperature=0.0,
)
prompts, answer, indices = prep_prompts(batch_size)
# We don't compare with the baseline model here, since the results
# slightly different due to different tailing in attention.
test_texts = get_text_from_llm_generator(test_llm_generator,
prompts,
sampling_params,
llm_cb=check_window(prompts))
check_answers(indices, answer, test_texts)
def prep_prompts(batch_size: int):
"""
Generate prompts which a bunch of assignments,
then asking for the value of one of them.
The prompt is just under 10k tokens; sliding window is 4k
so the answer is outside sliding window, but should still be correct.
"""
prompts: List[str] = []
answer: List[int] = []
indices: List[int] = []
random.seed(1)
for _ in range(batch_size):
idx = random.randint(30, 90)
indices.append(idx)
prompt = "```python\n# We set a number of variables, " + \
f"x{idx} will be important later\n"
ln = random.randint(800, 1100)
for k in range(30, ln):
v = random.randint(10, 99)
if k == idx:
answer.append(v)
prompt += f"x{k} = {v}\n"
prompt += f"# Now, we check the value of x{idx}:\n"
prompt += f"assert x{idx} == "
prompts.append(prompt)
return prompts, answer, indices
def check_answers(indices: List[int], answer: List[int], outputs: List[str]):
answer2 = [int(text[0:2].strip()) for text in outputs]
print(list(zip(indices, zip(answer, answer2))))
numok = 0
for a1, a2 in zip(answer, answer2):
if a1 == a2:
numok += 1
frac_ok = numok / len(answer)
print(f"Num OK: {numok}/{len(answer)} {frac_ok}")
assert frac_ok > 0.7
def check_window(prompts: List[str]):
def inner(llm: LLM):
sliding_window = llm.llm_engine.model_config.get_sliding_window()
assert sliding_window and sliding_window > 0
assert any(
len(llm.get_tokenizer().tokenize(prompt)) > sliding_window
for prompt in prompts)
return inner

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@ -101,3 +101,72 @@ def test_append_slots(block_size, prompt_len, num_slots_to_append,
range(prompt_len + num_slots_to_append + num_lookahead_slots)),
block_size)) - len(chunk_list(list(range(prompt_len)), block_size))
assert num_consumed_blocks == expected_consumed_blocks
@pytest.mark.parametrize("block_size", [8, 16])
@pytest.mark.parametrize("prompt_len", [10, 300, 1000])
@pytest.mark.parametrize("num_slots_to_append", [50])
@pytest.mark.parametrize("sliding_window", [20, 32, 200, 512])
def test_sliding_window(block_size, prompt_len, num_slots_to_append,
sliding_window):
"""Verify append_slots consumes the correct number of blocks from the block
table.
"""
num_gpu_blocks = 1024
watermark = 0.1
block_manager = BlockSpaceManagerV2(
block_size=block_size,
num_gpu_blocks=num_gpu_blocks,
num_cpu_blocks=0,
watermark=watermark,
sliding_window=sliding_window,
)
def check_used(min_n, max_n=None):
if max_n is None:
max_n = min_n
used = num_gpu_blocks - block_manager.get_num_free_gpu_blocks()
#print("check", min_n, used, max_n)
assert min_n <= used
assert used <= max_n
def num_blocks(num_tokens):
return (num_tokens + block_size - 1) // block_size
check_used(0)
seq_group = create_seq_group(
seq_prompt_len=prompt_len,
seq_output_lens=[0],
)
check_used(0)
# Allocate seq
assert block_manager.can_allocate(seq_group)
block_manager.allocate(seq_group)
check_used(num_blocks(prompt_len))
# Seq seq to RUNNING
seq = seq_group.get_seqs()[0]
seq.status = SequenceStatus.RUNNING
seq.data.update_num_computed_tokens(prompt_len)
check_used(num_blocks(prompt_len))
# this is how we compute it in BlockSpaceManagerV2.__init__
sliding_blocks = (sliding_window // block_size) + 2
# plus one block for null block
sliding_blocks += 1
# Append tokens to the sequeqnce
for token_id in range(num_slots_to_append):
seq.append_token_id(token_id, {token_id: Logprob(0.0)})
seq.data.update_num_computed_tokens(1)
block_manager.append_slots(seq, num_lookahead_slots=0)
if prompt_len < sliding_window + 10:
check_used(0, sliding_blocks + 1)
else:
check_used(sliding_blocks, sliding_blocks + 1)