vllm/tests/kernels/test_blocksparse_attention.py
Russell Bryant e489ad7a21
[Misc] Add SPDX-License-Identifier headers to python source files (#12628)
- **Add SPDX license headers to python source files**
- **Check for SPDX headers using pre-commit**

commit 9d7ef44c3cfb72ca4c32e1c677d99259d10d4745
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:18:24 2025 -0500

    Add SPDX license headers to python source files
    
This commit adds SPDX license headers to python source files as
recommended to
the project by the Linux Foundation. These headers provide a concise way
that is
both human and machine readable for communicating license information
for each
source file. It helps avoid any ambiguity about the license of the code
and can
    also be easily used by tools to help manage license compliance.
    
The Linux Foundation runs license scans against the codebase to help
ensure
    we are in compliance with the licenses of the code we use, including
dependencies. Having these headers in place helps that tool do its job.
    
    More information can be found on the SPDX site:
    
    - https://spdx.dev/learn/handling-license-info/
    
    Signed-off-by: Russell Bryant <rbryant@redhat.com>

commit 5a1cf1cb3b80759131c73f6a9dddebccac039dea
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:36:32 2025 -0500

    Check for SPDX headers using pre-commit
    
    Signed-off-by: Russell Bryant <rbryant@redhat.com>

---------

Signed-off-by: Russell Bryant <rbryant@redhat.com>
2025-02-02 11:58:18 -08:00

442 lines
15 KiB
Python

# SPDX-License-Identifier: Apache-2.0
import random
from typing import List, Optional, Tuple
import pytest
import torch
from vllm import _custom_ops as ops
from vllm.attention.ops.blocksparse_attention.interface import (
LocalStridedBlockSparseAttn)
from vllm.platforms import current_platform
from vllm.utils import get_max_shared_memory_bytes
from .allclose_default import get_default_atol, get_default_rtol
FLOAT32_BYTES = torch.finfo(torch.float).bits // 8
# This will change depending on the compute capability.
# - 512 as a buffer
MAX_SEQ_LEN = get_max_shared_memory_bytes() // FLOAT32_BYTES - 512
# MAX_SEQ_LEN = 2771
# There may not be enough gpu memory due to large NUM_BLOCKS.
# Reduce NUM_BLOCKS when it happens.
NUM_BLOCKS = 4321 # Arbitrary values for testing
PARTITION_SIZE = 512
DTYPES = [torch.half, torch.bfloat16]
NUM_GEN_SEQS = [3] # Arbitrary values for testing
NUM_PREFILL_SEQS = [3] # Arbitrary values for testing
NUM_HEADS = [(40, 40)] # Arbitrary values for testing
HEAD_SIZES = [64, 112]
BLOCK_SIZES = [16]
USE_ALIBI = [False, True]
KV_CACHE_DTYPE = ["auto", "fp8"]
SEEDS = [0]
CUDA_DEVICES = ['cuda:0']
BLOCKSPARSE_LOCAL_BLOCKS = [16]
BLOCKSPARSE_VERT_STRIDES = [8]
BLOCKSPARSE_BLOCK_SIZES = [64]
BLOCKSPARSE_HEADS_SLIDINGS = [2, -1]
BLOCKSPARSE_HOMO_HEADS = [True, False]
def ref_masked_attention(
query: torch.Tensor,
key: torch.Tensor,
value: torch.Tensor,
scale: float,
attn_mask: Optional[torch.Tensor] = None,
) -> torch.Tensor:
attn_weights = scale * torch.einsum("qhd,khd->hqk", query, key).float()
if attn_mask is not None:
attn_weights = attn_weights + attn_mask.float()
attn_weights = torch.softmax(attn_weights, dim=-1).to(value.dtype)
out = torch.einsum("hqk,khd->qhd", attn_weights, value)
return out
def ref_single_query_cached_kv_attention(
output: torch.Tensor,
query: torch.Tensor,
num_queries_per_kv: int,
key_cache: torch.Tensor,
value_cache: torch.Tensor,
block_tables: torch.Tensor,
seq_lens: torch.Tensor,
scale: float,
alibi_slopes: Optional[torch.Tensor],
tp_rank: int = 0,
blocksparse_local_blocks: int = 0,
blocksparse_vert_stride: int = 1,
blocksparse_block_size: int = 64,
blocksparse_head_sliding_step: int = 0,
) -> None:
num_query_heads = query.shape[1]
num_kv_heads = value_cache.shape[1]
head_size = value_cache.shape[2]
block_size = value_cache.shape[3]
num_seqs = query.shape[0]
block_tables_lst = block_tables.cpu().tolist()
seq_lens_lst = seq_lens.cpu().tolist()
for i in range(num_seqs):
q = query[i].unsqueeze(0)
block_table = block_tables_lst[i]
seq_len = int(seq_lens_lst[i])
keys_lst: List[torch.Tensor] = []
values_lst: List[torch.Tensor] = []
for j in range(seq_len):
block_number = int(block_table[j // block_size])
block_offset = j % block_size
k = key_cache[block_number, :, :, block_offset, :]
k = k.reshape(num_kv_heads, head_size)
keys_lst.append(k)
v = value_cache[block_number, :, :, block_offset]
values_lst.append(v)
keys = torch.stack(keys_lst, dim=0)
values = torch.stack(values_lst, dim=0)
if num_queries_per_kv > 1:
# Handle MQA and GQA
keys = torch.repeat_interleave(keys, num_queries_per_kv, dim=1)
values = torch.repeat_interleave(values, num_queries_per_kv, dim=1)
alibi_bias = None
if alibi_slopes is not None:
# Create the ALiBi bias used in the paged attention kernel.
position_ids = torch.arange(seq_len).int()
alibi_bias = (position_ids - seq_len + 1).float()
alibi_bias = alibi_slopes.view(-1, 1, 1) * alibi_bias.view(
1, 1, -1)
if blocksparse_vert_stride >= 1:
bsize = blocksparse_block_size
hsliding = blocksparse_head_sliding_step
vert = blocksparse_vert_stride
locals = blocksparse_local_blocks
qb = (seq_len - 1) // bsize
attn_mask = q.new_zeros(
(num_query_heads, 1, seq_len)).float() - torch.inf
for h in range(num_query_heads):
if hsliding >= 0: # slide with q heads
bs_offset = (tp_rank * num_query_heads + h) * hsliding + 1
else: # slide with kv heads
bs_offset = (tp_rank * num_kv_heads +
h // num_queries_per_kv) * (-hsliding) + 1
for kb in range(qb + 1):
kj = kb * bsize
if (qb - kb) < locals or \
(kb + bs_offset) % vert == 0:
attn_mask[h, 0, kj:min(kj + bsize, seq_len)] = 0
if alibi_bias is not None:
attn_mask += alibi_bias
else:
attn_mask = alibi_bias
out = ref_masked_attention(q, keys, values, scale, attn_mask=attn_mask)
out = out.view(num_query_heads, head_size)
output[i].copy_(out, non_blocking=True)
@pytest.mark.parametrize("version", ["v1", "v2"])
@pytest.mark.parametrize("num_seqs", NUM_GEN_SEQS)
@pytest.mark.parametrize("num_heads", NUM_HEADS)
@pytest.mark.parametrize("head_size", HEAD_SIZES)
@pytest.mark.parametrize("use_alibi", USE_ALIBI)
@pytest.mark.parametrize("block_size", BLOCK_SIZES)
@pytest.mark.parametrize("dtype", DTYPES)
@pytest.mark.parametrize("kv_cache_dtype", KV_CACHE_DTYPE)
@pytest.mark.parametrize("seed", SEEDS)
@pytest.mark.parametrize("device", CUDA_DEVICES)
@pytest.mark.parametrize("blocksparse_local_blocks", BLOCKSPARSE_LOCAL_BLOCKS)
@pytest.mark.parametrize("blocksparse_vert_stride", BLOCKSPARSE_VERT_STRIDES)
@pytest.mark.parametrize("blocksparse_block_size", BLOCKSPARSE_BLOCK_SIZES)
@pytest.mark.parametrize("blocksparse_head_sliding_step",
BLOCKSPARSE_HEADS_SLIDINGS)
def test_paged_attention(
kv_cache_factory,
version: str,
num_seqs: int,
num_heads: Tuple[int, int],
head_size: int,
use_alibi: bool,
block_size: int,
dtype: torch.dtype,
kv_cache_dtype: str,
seed: int,
device: str,
blocksparse_local_blocks: int,
blocksparse_vert_stride: int,
blocksparse_block_size: int,
blocksparse_head_sliding_step: int,
) -> None:
current_platform.seed_everything(seed)
torch.set_default_device(device)
scale = float(1.0 / (head_size**0.5))
num_query_heads, num_kv_heads = num_heads
query = torch.empty(num_seqs, num_query_heads, head_size, dtype=dtype)
query.uniform_(-scale, scale)
assert num_query_heads % num_kv_heads == 0
num_queries_per_kv = num_query_heads // num_kv_heads
alibi_slopes = None
if use_alibi:
alibi_slopes = torch.rand(num_query_heads, dtype=torch.float)
seq_lens = [random.randint(1, MAX_SEQ_LEN) for _ in range(num_seqs)]
seq_lens[-1] = MAX_SEQ_LEN
max_seq_len = max(seq_lens)
seq_lens = torch.tensor(seq_lens, dtype=torch.int)
# Create the block tables.
max_num_blocks_per_seq = (max_seq_len + block_size - 1) // block_size
block_tables = []
for _ in range(num_seqs):
block_table = [
random.randint(0, NUM_BLOCKS - 1)
for _ in range(max_num_blocks_per_seq)
]
block_tables.append(block_table)
block_tables = torch.tensor(block_tables, dtype=torch.int)
# Create the KV caches.
key_caches, value_caches = kv_cache_factory(NUM_BLOCKS, block_size, 1,
num_kv_heads, head_size,
kv_cache_dtype, dtype, seed,
device)
key_cache, value_cache = key_caches[0], value_caches[0]
# Using default kv_scale
k_scale = v_scale = torch.tensor(1.0, dtype=torch.float32, device=device)
tp_rank = 0
# Call the paged attention kernel.
output = torch.empty_like(query)
if version == "v1":
ops.paged_attention_v1(
output,
query,
key_cache,
value_cache,
num_kv_heads,
scale,
block_tables,
seq_lens,
block_size,
max_seq_len,
alibi_slopes,
kv_cache_dtype,
k_scale,
v_scale,
tp_rank=tp_rank,
blocksparse_local_blocks=blocksparse_local_blocks,
blocksparse_vert_stride=blocksparse_vert_stride,
blocksparse_block_size=blocksparse_block_size,
blocksparse_head_sliding_step=blocksparse_head_sliding_step,
)
elif version == "v2":
num_partitions = ((max_seq_len + PARTITION_SIZE - 1) // PARTITION_SIZE)
assert PARTITION_SIZE % block_size == 0
num_seqs, num_heads, head_size = output.shape
tmp_output = torch.empty(
size=(num_seqs, num_heads, num_partitions, head_size),
dtype=output.dtype,
)
exp_sums = torch.empty(
size=(num_seqs, num_heads, num_partitions),
dtype=torch.float32,
)
max_logits = torch.empty_like(exp_sums)
ops.paged_attention_v2(
output,
exp_sums,
max_logits,
tmp_output,
query,
key_cache,
value_cache,
num_kv_heads,
scale,
block_tables,
seq_lens,
block_size,
max_seq_len,
alibi_slopes,
kv_cache_dtype,
k_scale,
v_scale,
tp_rank=tp_rank,
blocksparse_local_blocks=blocksparse_local_blocks,
blocksparse_vert_stride=blocksparse_vert_stride,
blocksparse_block_size=blocksparse_block_size,
blocksparse_head_sliding_step=blocksparse_head_sliding_step,
)
else:
raise AssertionError(f"Unknown version: {version}")
# Run the reference implementation.
if kv_cache_dtype == "fp8":
# Convert cache data back to dtype.
x = 16 // torch.tensor([], dtype=dtype).element_size()
key_cache_shape = (NUM_BLOCKS, num_kv_heads, head_size // x,
block_size, x)
dequantized_key_cache = torch.empty(size=key_cache_shape,
dtype=dtype,
device=device)
ops.convert_fp8(dequantized_key_cache, key_cache)
key_cache = dequantized_key_cache
value_cache_shape = value_cache.shape
dequantized_value_cache = torch.empty(size=value_cache_shape,
dtype=dtype,
device=device)
ops.convert_fp8(dequantized_value_cache, value_cache)
value_cache = dequantized_value_cache
ref_output = torch.empty_like(query)
ref_single_query_cached_kv_attention(
ref_output,
query,
num_queries_per_kv,
key_cache,
value_cache,
block_tables,
seq_lens,
scale,
alibi_slopes,
tp_rank,
blocksparse_local_blocks,
blocksparse_vert_stride,
blocksparse_block_size,
blocksparse_head_sliding_step,
)
# NOTE(woosuk): Due to the kernel-level differences in the two
# implementations, there is a small numerical difference in the two
# outputs. Thus, we use a relaxed tolerance for the test.
atol = get_default_atol(output) if current_platform.is_rocm() else 1e-3
rtol = get_default_rtol(output) if current_platform.is_rocm() else 1e-5
# NOTE(zhaoyang): FP8 KV Cache will introduce quantization error,
# so we use a relaxed tolerance for the test.
atol, rtol = 1e-3, 1e-5
if kv_cache_dtype == "fp8":
atol, rtol = 1e-2, 1e-5
torch.testing.assert_close(output, ref_output, atol=atol, rtol=rtol)
def ref_multi_query_kv_attention(
cu_seq_lens: List[int],
query: torch.Tensor,
key: torch.Tensor,
value: torch.Tensor,
scale: float,
dtype: torch.dtype,
) -> torch.Tensor:
num_seqs = len(cu_seq_lens) - 1
ref_outputs = []
for i in range(num_seqs):
start_idx = cu_seq_lens[i]
end_idx = cu_seq_lens[i + 1]
seq_len = end_idx - start_idx
# Create attention mask.
attn_mask = torch.triu(torch.ones(seq_len, seq_len, dtype=dtype),
diagonal=1)
attn_mask = attn_mask * torch.finfo(dtype).min
attn_mask = attn_mask.to(dtype=dtype)
ref_output = ref_masked_attention(
query[start_idx:end_idx],
key[start_idx:end_idx],
value[start_idx:end_idx],
scale,
attn_mask=attn_mask,
)
ref_outputs.append(ref_output)
ref_output = torch.cat(ref_outputs, dim=0)
return ref_output
@pytest.mark.parametrize("num_seqs", NUM_PREFILL_SEQS)
@pytest.mark.parametrize("num_heads", NUM_HEADS)
@pytest.mark.parametrize("head_size", HEAD_SIZES)
@pytest.mark.parametrize("blocksparse_local_blocks", BLOCKSPARSE_LOCAL_BLOCKS)
@pytest.mark.parametrize("blocksparse_vert_stride", BLOCKSPARSE_VERT_STRIDES)
@pytest.mark.parametrize("blocksparse_block_size", BLOCKSPARSE_BLOCK_SIZES)
@pytest.mark.parametrize("blocksparse_homo_heads", BLOCKSPARSE_HOMO_HEADS)
@pytest.mark.parametrize("dtype", DTYPES)
@pytest.mark.parametrize("seed", SEEDS)
@pytest.mark.parametrize("device", CUDA_DEVICES)
@torch.inference_mode()
def test_varlen_blocksparse_attention_prefill(
num_seqs: int,
num_heads: Tuple[int, int],
head_size: int,
blocksparse_local_blocks: int,
blocksparse_vert_stride: int,
blocksparse_block_size: int,
blocksparse_homo_heads: bool,
dtype: torch.dtype,
seed: int,
device: str,
) -> None:
current_platform.seed_everything(seed)
torch.set_default_device(device)
# MAX_SEQ_LEN sometimes causes OOM in the reference implementation.
# As the xformers library is already tested with its own tests, we can use
# a smaller MAX_SEQ_LEN here.
max_len = min(MAX_SEQ_LEN, 4096)
seq_lens = random.sample(range(1, max_len), num_seqs)
cu_seq_lens = torch.cumsum(torch.tensor([0] + seq_lens), dim=0)
num_tokens = sum(seq_lens)
scale = float(1.0 / (head_size**0.5))
num_query_heads, num_kv_heads = num_heads
assert num_query_heads % num_kv_heads == 0
num_queries_per_kv = num_query_heads // num_kv_heads
qkv = torch.empty(num_tokens,
num_query_heads + 2 * num_kv_heads,
head_size,
dtype=dtype)
qkv.uniform_(-scale, scale)
query, key, value = qkv.split(
[num_query_heads, num_kv_heads, num_kv_heads], dim=1)
bs_attn_op = LocalStridedBlockSparseAttn(
num_query_heads,
max_len,
local_blocks=blocksparse_local_blocks,
vert_stride=blocksparse_vert_stride,
block_size=blocksparse_block_size,
device=device,
dtype=dtype,
homo_head=blocksparse_homo_heads)
output = bs_attn_op(query,
key,
value,
cu_seq_lens.to(device),
sm_scale=scale)
if num_queries_per_kv > 1:
# Handle MQA and GQA
key = torch.repeat_interleave(key, num_queries_per_kv, dim=1)
value = torch.repeat_interleave(value, num_queries_per_kv, dim=1)
ref_output = ref_multi_query_kv_attention(
cu_seq_lens.tolist(),
query,
key,
value,
scale,
dtype,
)
torch.testing.assert_close(output, ref_output, atol=1e-2, rtol=1e-2)