vllm/tests/v1/core/test_specialized_manager.py
Chen Zhang 3a5f0afcd2
[V1] Implement sliding window attention in kv_cache_manager (#14097)
Signed-off-by: Chen Zhang <zhangch99@outlook.com>
2025-04-01 00:33:17 -07:00

139 lines
5.1 KiB
Python

# SPDX-License-Identifier: Apache-2.0
import torch
from vllm.v1.core.block_pool import BlockPool
from vllm.v1.core.kv_cache_utils import BlockHashType, KVCacheBlock
from vllm.v1.core.specialized_manager import SlidingWindowManager
from vllm.v1.kv_cache_interface import SlidingWindowSpec
def test_sliding_window_possible_cached_prefix():
sliding_window_spec = SlidingWindowSpec(
block_size=2,
num_kv_heads=1,
head_size=1,
dtype=torch.float32,
sliding_window=4,
use_mla=False,
)
block_pool = BlockPool(num_gpu_blocks=100, enable_caching=True)
manager = SlidingWindowManager(sliding_window_spec, block_pool)
def run_one_case(block_is_cached, expect_length):
block_hash_list = [
BlockHashType(i, ()) for i in range(len(block_is_cached))
]
block_pool.cached_block_hash_to_block.clear()
# Mock the block pool with the cached blocks
for i, (block_hash,
is_cached) in enumerate(zip(block_hash_list, block_is_cached)):
if is_cached:
block_pool.cached_block_hash_to_block[block_hash] = {
i: block_pool.blocks[i + 10]
}
computed_blocks = manager.find_longest_cache_hit(block_hash_list)
assert len(computed_blocks) == expect_length
assert all(block == block_pool.null_block
for block in computed_blocks[:expect_length - 2])
for i in range(2):
if i < expect_length:
block_index = expect_length - i - 1
assert computed_blocks[
block_index].block_id == block_index + 10
run_one_case([False] * 10, 0)
run_one_case([True], 1)
run_one_case([True, False], 1)
run_one_case([True, True], 2)
run_one_case([True, True, False], 2)
run_one_case([True, True, True], 3)
run_one_case([True, True, True, False], 3)
run_one_case([
True, True, False, True, False, False, True, True, False, True, True,
True
], 12)
run_one_case([
True, True, False, True, False, False, True, True, False, False, False
], 8)
run_one_case([
True, True, False, True, False, False, True, True, False, False, False,
True
], 8)
def test_sliding_window_remove_skipped_blocks():
sliding_window_spec = SlidingWindowSpec(
block_size=2,
num_kv_heads=1,
head_size=1,
dtype=torch.float32,
sliding_window=4,
use_mla=False,
)
block_pool = BlockPool(num_gpu_blocks=2000, enable_caching=True)
manager = SlidingWindowManager(sliding_window_spec, block_pool)
null_block_id = block_pool.null_block.block_id
def id_to_block_table(ids):
return [
KVCacheBlock(id_)
if id_ != null_block_id else block_pool.null_block for id_ in ids
]
def assert_block_id(block_table, ids):
for block, id_ in zip(block_table, ids):
if id_ == null_block_id:
assert block == block_pool.null_block
else:
assert block.block_id == id_
original_block_ids = [
1000, 1001, 1002, 1003, 1004, 1005, 1006, 1007, 1008, 1009, 1010
]
block_table = id_to_block_table(original_block_ids)
removed = manager.remove_skipped_blocks(block_table, 0)
assert_block_id(removed, [])
assert_block_id(block_table, original_block_ids)
# 4 tokens are computed. Only token 0 is out of the sliding window. As
# block 1000 also contains token 1 that is in the sliding window, block 1000
# cannot be removed.
removed = manager.remove_skipped_blocks(block_table, 4)
assert_block_id(removed, [])
assert_block_id(block_table, original_block_ids)
# 5 tokens are computed. Token 0 & 1 are out of the sliding window.
# Block 1000 can be removed.
removed = manager.remove_skipped_blocks(block_table, 5)
assert_block_id(removed, [original_block_ids[0]])
assert_block_id(block_table, [null_block_id] + original_block_ids[1:])
# 6 tokens are computed. Token 0-2 are out of the sliding window.
# Cannot remove new block as the block 1001 is still used by token 3.
removed = manager.remove_skipped_blocks(block_table, 6)
assert_block_id(removed, [])
assert_block_id(block_table, [null_block_id] + original_block_ids[1:])
# 7 tokens are computed. Token 0-3 are out of the sliding window.
# Block 1001 can be removed and block 1000 is already removed.
removed = manager.remove_skipped_blocks(block_table, 7)
assert_block_id(removed, [original_block_ids[1]])
assert_block_id(block_table, [null_block_id] * 2 + original_block_ids[2:])
# 11 tokens are computed. Token 0-7 are out of the sliding window.
# Block 1002 & 1003 can be removed now. Block 1003 represents a longer
# sequence, and is expected to be evicted earlier than 1002, so the order
# of removed blocks should be [1003, 1002].
removed = manager.remove_skipped_blocks(block_table, 11)
assert_block_id(removed, [original_block_ids[3], original_block_ids[2]])
assert_block_id(block_table, [null_block_id] * 4 + original_block_ids[4:])