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[Perf][PCP][DCP] add multi-stream for GQA to enable computation-communication overlap (#5382)

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### What this PR does / why we need it?
This PR adds multi-stream for GQA to enable computation-communication
overlap. For chunked prefill, we reduce TTFT by approximately 4%.

### Does this PR introduce _any_ user-facing change?
No

- vLLM version: release/v0.13.0
- vLLM main:
bc0a5a0c08

---------

Signed-off-by: QiuChunshuo <qiuchunshuo@huawei.com>
This commit is contained in:
Qiu
2026-01-04 16:33:18 +08:00
committed by GitHub
parent 37fd48bee5
commit 7c210225a2
5 changed files with 276 additions and 224 deletions
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196
tests/ut/attention/test_attention_cp.py
View File

@@ -1,8 +1,9 @@
from functools import wraps
from typing import List
from unittest.mock import MagicMock, patch
import torch
from vllm.distributed.parallel_state import GroupCoordinator
from vllm.distributed.parallel_state import GroupCoordinator, all_gather_fake
from tests.ut.base import TestBase
from vllm_ascend.attention.attention_cp import AscendAttentionCPImpl
@@ -10,33 +11,60 @@ from vllm_ascend.attention.attention_v1 import (AscendMetadata,
AscendMetadataForPrefill)
def patch_distributed_groups(dcp_size=1, dcp_rank=0, pcp_size=1, pcp_rank=0):
"""
Decorator to patch common distributed group mocks with configuration
Args:
dcp_size: DCP world size (default: 1)
dcp_rank: DCP rank (default: 0)
pcp_size: PCP world size (default: 1)
pcp_rank: PCP rank (default: 0)
"""
def decorator(func):
@wraps(func)
@patch('torch.distributed.all_to_all_single')
@patch('vllm.distributed.parallel_state._PCP')
def wrapper(self, mock_pcp, mock_all_to_all_single, *args, **kwargs):
mock_pcp.world_size = pcp_size
mock_pcp.rank_in_group = pcp_rank
mock_pcp.rank_in_group = pcp_rank
mock_pcp.world_size = pcp_size
mock_pcp.device_group = MagicMock()
mock_pcp.all_gather = MagicMock()
mock_pcp.all_gather.side_effect = lambda input_, dim: all_gather_fake(
input_, dim, pcp_size, "mock")
mock_all_to_all_single.side_effect = lambda output, input, *a, **kw: output.copy_(
input)
return func(self, mock_all_to_all_single, mock_pcp, *args,
**kwargs)
return wrapper
return decorator
class TestAscendAttentionCPImpl(TestBase):
@patch('vllm_ascend.attention.attention_cp.get_pcp_group')
@patch('vllm.distributed.parallel_state._PCP',
new_callable=lambda: MagicMock(spec=GroupCoordinator))
@patch('vllm_ascend.attention.attention_cp.get_dcp_group')
@patch('vllm.distributed.parallel_state._DCP',
new_callable=lambda: MagicMock(spec=GroupCoordinator))
@patch("vllm.distributed.get_decode_context_model_parallel_world_size",
return_value=1)
def setUp(self, mock_get_dcp_size, mock_dcp, mock_get_dcp_group, mock_pcp,
mock_get_pcp_group):
def setUp(self, mock_get_dcp_size, mock_dcp, mock_pcp):
mock_dcp.world_size = 2
mock_dcp.rank_in_group = 0
dcp_group = MagicMock(spec=GroupCoordinator)
dcp_group.rank_in_group = 0
dcp_group.world_size = 2
dcp_group.device_group = MagicMock()
mock_get_dcp_group.return_value = dcp_group
mock_dcp.device_group = MagicMock()
mock_pcp.world_size = 2
mock_pcp.rank_in_group = 0
pcp_group = MagicMock(spec=GroupCoordinator)
pcp_group.rank_in_group = 0
pcp_group.world_size = 2
pcp_group.device_group = MagicMock()
mock_get_pcp_group.return_value = pcp_group
mock_pcp.device_group = MagicMock()
self.layer = MagicMock()
self.layer.layer_name = "test_layer"
@@ -237,10 +265,14 @@ class TestAscendAttentionCPImpl(TestBase):
attn_metadata = MagicMock()
attn_metadata.prefill = MagicMock()
attn_metadata.prefill.chunked_context = MagicMock()
attn_metadata.prefill.chunked_context.local_context_lens_allranks = torch.tensor(
[[[256, 256], [256, 256]]])
local_context_lens_allranks = torch.tensor([[[256, 256], [256, 256]]])
attn_metadata.prefill.chunked_context.local_context_lens_allranks = local_context_lens_allranks
attn_metadata.prefill.chunked_context.batch_chunk_seq_mask = torch.randint(
0, 2, (1024, ), dtype=torch.bool)
attn_metadata.prefill.chunked_context.local_total_toks = local_context_lens_allranks[:,
0,
0].sum(
)
def mock_load_kv_for_chunk(attn_metadata, kv_cache,
local_chunked_kv_lens_rank, query,
@@ -264,8 +296,17 @@ class TestAscendAttentionCPImpl(TestBase):
batch_size,
num_heads, 1)
result_output, result_lse = self.impl._compute_prefill_context(
context_output = self.impl._compute_prefill_context(
query, kv_cache, attn_metadata)
local_context_output = torch.cat(context_output,
dim=-1).permute([1, 2,
0]).contiguous()
global_context_output = self.impl._gather_global_context_output(
local_context_output)
global_context_output = global_context_output.permute([2, 0, 1
]).contiguous()
result_output, result_lse = self.impl._update_global_context_output(
global_context_output)
self.assertEqual(result_output.shape[0], batch_size)
self.assertEqual(result_output.shape[1], self.impl.num_heads)
@@ -687,37 +728,25 @@ class TestUpdateNpuAttnOutLse(TestBase):
self.assertIsInstance(out_final, torch.Tensor)
self.assertIsInstance(lse_final, torch.Tensor)
@patch('vllm_ascend.attention.attention_cp.get_pcp_group')
@patch('vllm.distributed.parallel_state._PCP',
new_callable=lambda: MagicMock(spec=GroupCoordinator))
@patch('torch.cat')
@patch('torch.distributed.all_to_all_single')
@patch('torch.distributed.all_gather')
@patch('torch.stack')
@patch('torch.split')
def test_update_chunk_attn_out_lse_dcp_pcp_both_greater_than_1(
self, mock_split, mock_stack, mock_all_gather,
mock_all_to_all_single, mock_cat, mock_pcp, mock_get_pcp_group):
@patch_distributed_groups(dcp_size=2, pcp_size=3)
def test_update_chunk_attn_out_lse_dcp2_pcp3(self, mock_all_to_all_single,
mock_pcp):
# Mock input data
prefix_chunk_output = torch.randn(2, 4, 8)
prefix_chunk_lse = torch.randn(2, 4, 1)
self.impl.dcp_size = 2
self.impl.pcp_size = 3
self.impl.head_size = 8
# Mock output
mock_cat.return_value = torch.randn(2, 4, 9)
mock_all_to_all_single.return_value = torch.randn(4, 9, 2)
mock_all_gather.return_value = [(2, 4, 9), (2, 4, 9), (2, 4, 9)]
mock_stack.return_value = torch.randn(6, 2, 2, 9)
mock_split.return_value = (torch.randn(6, 2, 2,
8), torch.randn(6, 2, 2, 1))
mock_pcp_group = MagicMock()
mock_pcp_group.all_gather.return_value = torch.randn(6, 4, 9)
mock_get_pcp_group.return_value = mock_pcp_group
# Call the method under test
output, lse = self.impl._update_chunk_attn_out_lse(
prefix_chunk_output, prefix_chunk_lse)
chunk_data = torch.cat([prefix_chunk_output, prefix_chunk_lse],
dim=-1).permute([1, 2, 0]).contiguous()
global_context_output = self.impl._gather_global_context_output(
chunk_data)
global_context_output = global_context_output.permute([2, 0, 1
]).contiguous()
output, lse = self.impl._update_global_context_output(
global_context_output)
# Assert the method call
self.assertIsInstance(output, torch.Tensor)
@@ -725,21 +754,12 @@ class TestUpdateNpuAttnOutLse(TestBase):
self.assertEqual(output.shape, (2, 2, 8))
self.assertEqual(lse.shape, (2, 2, 1))
self.assertEqual(mock_cat.call_count, 1)
mock_all_to_all_single.assert_called_once()
self.assertEqual(mock_get_pcp_group.call_count, 1)
mock_pcp.all_gather.assert_called_once()
@patch('vllm_ascend.attention.attention_cp.get_pcp_group')
@patch('vllm.distributed.parallel_state._PCP')
@patch('torch.cat')
@patch('torch.chunk')
@patch('torch.stack')
@patch('torch.split')
@patch('torch.distributed.all_to_all_single')
@patch('torch.distributed.all_gather')
def test_update_chunk_attn_out_lse_dcp_greater_than_1_only(
self, mock_all_gather, mock_all_to_all_single, mock_split,
mock_stack, mock_chunk, mock_cat, mock_pcp, mock_pcp_group):
@patch_distributed_groups(dcp_size=2)
def test_update_chunk_attn_out_lse_dcp2_pcp1(self, mock_all_to_all_single,
mock_pcp):
# Mock input data
prefix_chunk_output = torch.randn(2, 4, 8)
prefix_chunk_lse = torch.randn(2, 4, 1)
@@ -748,20 +768,15 @@ class TestUpdateNpuAttnOutLse(TestBase):
self.impl.pcp_size = 1
self.impl.head_size = 8
# Mock output
mock_cat.return_value = torch.randn(2, 4, 9)
mock_all_to_all_single.side_effect = lambda output, input, *args, **kwargs: output.copy_(
input)
mock_chunk.return_value = [torch.randn(2, 2, 9), torch.randn(2, 2, 9)]
mock_stack.return_value = torch.randn(2, 2, 2, 9)
mock_split.return_value = [
torch.randn(2, 2, 2, 8),
torch.randn(2, 2, 2, 1)
]
# Call the method under test
output, lse = self.impl._update_chunk_attn_out_lse(
prefix_chunk_output, prefix_chunk_lse)
chunk_data = torch.cat([prefix_chunk_output, prefix_chunk_lse],
dim=-1).permute([1, 2, 0]).contiguous()
global_context_output = self.impl._gather_global_context_output(
chunk_data)
global_context_output = global_context_output.permute([2, 0, 1
]).contiguous()
output, lse = self.impl._update_global_context_output(
global_context_output)
# Assert the method call
self.assertIsInstance(output, torch.Tensor)
@@ -769,24 +784,12 @@ class TestUpdateNpuAttnOutLse(TestBase):
self.assertEqual(output.shape, (2, 2, 8))
self.assertEqual(lse.shape, (2, 2, 1))
self.assertEqual(mock_cat.call_count, 1)
mock_all_to_all_single.assert_called_once()
mock_all_gather.assert_not_called()
mock_pcp.all_gather.assert_not_called()
@patch('vllm_ascend.attention.attention_cp.get_pcp_group')
@patch('vllm.distributed.parallel_state._PCP')
@patch('torch.cat')
@patch('torch.stack')
@patch('torch.split')
@patch('torch.distributed.all_to_all_single')
@patch('torch.distributed.all_gather')
@patch(
'vllm_ascend.attention.attention_cp.AscendAttentionCPImpl._update_out_and_lse'
)
def test_update_chunk_attn_out_lse_pcp_greater_than_1_only(
self, mock_update_out_and_lse, mock_all_gather,
mock_all_to_all_single, mock_split, mock_stack, mock_cat, mock_pcp,
mock_get_pcp_group):
@patch_distributed_groups(pcp_size=2)
def test_update_chunk_attn_out_lse_dcp1_pcp2(self, mock_all_to_all_single,
mock_pcp):
# Mock input data
prefix_chunk_output = torch.randn(2, 4, 8)
prefix_chunk_lse = torch.randn(2, 4, 1)
@@ -795,30 +798,21 @@ class TestUpdateNpuAttnOutLse(TestBase):
self.impl.pcp_size = 2
self.impl.head_size = 8
# Mock output
mock_cat.return_value = torch.randn(2, 4, 9)
mock_pcp_group = MagicMock()
mock_pcp_group.all_gather.return_value = torch.randn(4, 4, 9)
mock_get_pcp_group.return_value = mock_pcp_group
mock_stack.return_value = torch.randn(2, 2, 4, 9)
mock_split.return_value = [
torch.randn(2, 2, 4, 8),
torch.randn(2, 2, 4, 1)
]
mock_update_out_and_lse.return_value = torch.randn(2, 4,
8), torch.randn(
2, 4, 1)
# Call the method under test
output, lse = self.impl._update_chunk_attn_out_lse(
prefix_chunk_output, prefix_chunk_lse)
chunk_data = torch.cat([prefix_chunk_output, prefix_chunk_lse],
dim=-1).permute([1, 2, 0]).contiguous()
global_context_output = self.impl._gather_global_context_output(
chunk_data)
global_context_output = global_context_output.permute([2, 0, 1
]).contiguous()
output, lse = self.impl._update_global_context_output(
global_context_output)
# Assert the method call
self.assertIsInstance(output, torch.Tensor)
self.assertIsInstance(lse, torch.Tensor)
self.assertEqual(output.shape, (2, 4, 8))
self.assertEqual(lse.shape, (2, 4, 1))
self.impl._update_out_and_lse.assert_called_once()
self.assertEqual(mock_cat.call_count, 1)
mock_all_to_all_single.assert_not_called()
mock_get_pcp_group.assert_called_once()
mock_pcp.all_gather.assert_called_once()

292
vllm_ascend/attention/attention_cp.py
View File

@@ -40,7 +40,7 @@ from vllm_ascend.attention.utils import (AscendCommonAttentionMetadata,
split_decodes_and_prefills)
from vllm_ascend.compilation.acl_graph import (get_graph_params,
update_graph_params_workspaces)
from vllm_ascend.utils import weak_ref_tensors
from vllm_ascend.utils import cp_chunkedprefill_comm_stream, weak_ref_tensors
class AscendAttentionCPMetadataBuilder(AscendAttentionMetadataBuilder):
@@ -152,6 +152,7 @@ class AscendAttentionCPMetadataBuilder(AscendAttentionMetadataBuilder):
dcp_rank]
actual_seq_lengths_kv = torch.cumsum(
local_chunked_kv_lens_rank, dim=0).tolist()
local_total_toks = local_chunked_kv_lens_rank.sum()
chunked_req_mask = self._get_chunked_req_mask(
local_context_lens_allranks)
local_chunk_starts = torch.zeros(
@@ -181,7 +182,8 @@ class AscendAttentionCPMetadataBuilder(AscendAttentionMetadataBuilder):
cp_kv_recover_idx_for_chunk=cp_kv_recover_idx_for_chunk,
kv_inverse_idx_for_chunk=kv_inverse_idx_for_chunk,
batch_chunk_seq_mask=batch_chunk_seq_mask,
chunk_seq_mask_filtered_indices=chunk_seq_mask_filtered_indices
chunk_seq_mask_filtered_indices=chunk_seq_mask_filtered_indices,
local_total_toks=local_total_toks.item()
)
attn_mask_seqlens = common_long_seq_metadata.attn_mask_seqlens
head_attn_nomask_seqlens = common_long_seq_metadata.head_attn_nomask_seqlens
@@ -372,6 +374,25 @@ class AscendAttentionCPImpl(AscendAttentionBackendImpl):
def _forward_prefill_cp(self, query: torch.Tensor, key: torch.Tensor,
value: torch.Tensor,
attn_metadata: AscendMetadata) -> torch.Tensor:
data_head, data_tail = self._forward_prefill_cp_pre(
query, key, value, attn_metadata)
output_head, lse_head = self._forward_prefill_cp_attn(
data_head, True, attn_metadata)
output_tail, lse_tail = self._forward_prefill_cp_attn(
data_tail, False, attn_metadata)
output, attn_lse = self._forward_prefill_cp_post(
[output_head, output_tail],
[lse_head, lse_tail],
attn_metadata,
)
return output, attn_lse
def _forward_prefill_cp_pre(self, query: torch.Tensor, key: torch.Tensor,
value: torch.Tensor,
attn_metadata: AscendMetadata) -> torch.Tensor:
assert attn_metadata is not None
assert attn_metadata.prefill is not None
assert attn_metadata.prefill.pcp_metadata is not None
@@ -382,48 +403,53 @@ class AscendAttentionCPImpl(AscendAttentionBackendImpl):
kv_with_q_head_mask_idx = attn_metadata.prefill.pcp_metadata.kv_with_q_head_mask_idx
kv_with_q_tail_nomask_idx = attn_metadata.prefill.pcp_metadata.kv_with_q_tail_nomask_idx
kv_with_q_tail_mask_idx = attn_metadata.prefill.pcp_metadata.kv_with_q_tail_mask_idx
q_head = torch.index_select(query, 0, q_head_idx)
q_tail = torch.index_select(query, 0, q_tail_idx)
k_head_nomask=torch.index_select(key, 0, kv_with_q_head_nomask_idx) \
if self.pcp_rank > 0 else None
v_head_nomask=torch.index_select(value, 0, kv_with_q_head_nomask_idx) \
if self.pcp_rank > 0 else None
k_head_mask = torch.index_select(key, 0, kv_with_q_head_mask_idx)
v_head_mask = torch.index_select(value, 0, kv_with_q_head_mask_idx)
k_tail_nomask = torch.index_select(key, 0, kv_with_q_tail_nomask_idx)
v_tail_nomask = torch.index_select(value, 0, kv_with_q_tail_nomask_idx)
k_tail_mask = torch.index_select(key, 0, kv_with_q_tail_mask_idx)
v_tail_mask = torch.index_select(value, 0, kv_with_q_tail_mask_idx)
return {
"q": q_head,
"k_nomask": k_head_nomask,
"v_nomask": v_head_nomask,
"k_mask": k_head_mask,
"v_mask": v_head_mask,
}, {
"q": q_tail,
"k_nomask": k_tail_nomask,
"v_nomask": v_tail_nomask,
"k_mask": k_tail_mask,
"v_mask": v_tail_mask,
},
def _forward_prefill_cp_attn(self, data, is_head, attn_metadata):
attn_mask_seqlens = attn_metadata.prefill.pcp_metadata.attn_mask_seqlens
head_attn_nomask_seqlens = attn_metadata.prefill.pcp_metadata.head_attn_nomask_seqlens
tail_attn_nomask_seqlens = attn_metadata.prefill.pcp_metadata.tail_attn_nomask_seqlens
nomask_seqlens = attn_metadata.prefill.pcp_metadata.head_attn_nomask_seqlens \
if is_head else attn_metadata.prefill.pcp_metadata.tail_attn_nomask_seqlens
mask = attn_metadata.prefill.pcp_metadata.pcp_prefill_mask
# 1. Attention calculation in the first half of Q in load balancing
output_heads, lse_heads = self._attention_with_nomask_and_mask(
q=torch.index_select(query, 0, q_head_idx),
output, lse = self._attention_with_nomask_and_mask(
**data,
q_seqlens=attn_mask_seqlens,
k_nomask=torch.index_select(key, 0, kv_with_q_head_nomask_idx)
if self.pcp_rank > 0 else None,
v_nomask=torch.index_select(value, 0, kv_with_q_head_nomask_idx)
if self.pcp_rank > 0 else None,
kv_seqlens_nomask=head_attn_nomask_seqlens,
k_mask=torch.index_select(key, 0, kv_with_q_head_mask_idx),
v_mask=torch.index_select(value, 0, kv_with_q_head_mask_idx),
kv_seqlens_mask=attn_mask_seqlens,
mask=mask,
attn_metadata=attn_metadata)
# 2. the Attention calculation in the latter half of Q in load balancing
# pcp_rank0: Q3*KV0~KV2 + Q3*KV3
# pcp_rank1: Q2*KV0~KV1 + Q2*KV2
output_tails, lse_tails = self._attention_with_nomask_and_mask(
q=torch.index_select(query, 0, q_tail_idx),
q_seqlens=attn_mask_seqlens,
k_nomask=torch.index_select(key, 0, kv_with_q_tail_nomask_idx),
v_nomask=torch.index_select(value, 0, kv_with_q_tail_nomask_idx),
kv_seqlens_nomask=tail_attn_nomask_seqlens,
k_mask=torch.index_select(key, 0, kv_with_q_tail_mask_idx),
v_mask=torch.index_select(value, 0, kv_with_q_tail_mask_idx),
kv_seqlens_nomask=nomask_seqlens,
kv_seqlens_mask=attn_mask_seqlens,
mask=mask,
attn_metadata=attn_metadata)
return output, lse
def _forward_prefill_cp_post(self, outputs, lses, attn_metadata):
q_full_idx = attn_metadata.prefill.pcp_metadata.q_full_idx
output = torch.index_select(
torch.cat([output_heads, output_tails], dim=0), 0, q_full_idx)
output = torch.index_select(torch.cat(outputs, dim=0), 0, q_full_idx)
attn_lse = None
if attn_metadata.prefill is not None and attn_metadata.prefill.chunked_context is not None:
attn_lse = torch.index_select(
torch.cat([lse_heads, lse_tails], dim=0), 0, q_full_idx)
attn_lse = torch.index_select(torch.cat(lses, dim=0), 0,
q_full_idx)
return output, attn_lse
def _out_lse_reshape(self, attn_out: torch.Tensor,
@@ -598,19 +624,6 @@ class AscendAttentionCPImpl(AscendAttentionBackendImpl):
dim=0)
return out_final, lse_final
def _process_chunk_prefill(self, current_attn_output_prefill,
current_attn_lse_prefill, kv_cache,
prefill_query, attn_metadata):
if attn_metadata.prefill is not None and attn_metadata.prefill.chunked_context is not None:
prefill_query_all = self._prefill_query_all_gather(
attn_metadata, prefill_query)
attn_output_full_chunk, attn_lse_full_chunk = self._compute_prefill_context(
prefill_query_all, kv_cache, attn_metadata)
self._update_chunk_attn_out_lse_with_current_attn_out_lse(
current_attn_output_prefill, current_attn_lse_prefill,
attn_output_full_chunk, attn_lse_full_chunk, prefill_query,
attn_metadata)
def _update_chunk_attn_out_lse_with_current_attn_out_lse(
self, current_attn_output_prefill, current_attn_lse_prefill,
attn_output_full_chunk, attn_lse_full_chunk, prefill_query,
@@ -646,18 +659,14 @@ class AscendAttentionCPImpl(AscendAttentionBackendImpl):
current_attn_output_prefill.dtype)
def _prefill_query_all_gather(self, attn_metadata, prefill_query):
if self.dcp_size > 1:
prefill_query = get_dcp_group().all_gather(prefill_query, 1)
if self.pcp_size > 1:
prefill_query = get_pcp_group().all_gather(prefill_query, 0)
prefill_query_all = torch.index_select(prefill_query,
0,
attn_metadata.prefill.chunked_context.cp_kv_recover_idx_for_chunk) \
if self.pcp_size > 1 else prefill_query
return prefill_query_all
prefill_query = torch.index_select(
prefill_query, 0, attn_metadata.prefill.chunked_context.
cp_kv_recover_idx_for_chunk)
if self.dcp_size > 1:
prefill_query = get_dcp_group().all_gather(prefill_query, 1)
return prefill_query
def _compute_prefill_context(self, query: torch.Tensor,
kv_cache: Tuple[torch.Tensor],
@@ -672,8 +681,7 @@ class AscendAttentionCPImpl(AscendAttentionBackendImpl):
local_chunked_kv_lens_rank = local_chunked_kv_lens[:, self.pcp_rank,
self.dcp_rank]
total_toks = local_chunked_kv_lens_rank.sum()
total_toks = prefill_metadata.chunked_context.local_total_toks
key, value = self._load_kv_for_chunk(attn_metadata, kv_cache,
local_chunked_kv_lens_rank, query,
total_toks)
@@ -682,16 +690,7 @@ class AscendAttentionCPImpl(AscendAttentionBackendImpl):
else:
num_heads = self.num_heads
prefix_chunk_output = torch.full(
(query.size(0), num_heads, self.head_size),
fill_value=0,
dtype=query.dtype,
device=query.device)
prefix_chunk_lse = torch.full((query.size(0), num_heads, 1),
fill_value=-torch.inf,
dtype=torch.float32,
device=query.device)
prefix_chunk_output, prefix_chunk_lse = None, None
if total_toks > 0:
prefix_chunk_output, prefix_chunk_lse = torch.ops.npu.npu_fused_infer_attention_score(
query,
@@ -711,59 +710,12 @@ class AscendAttentionCPImpl(AscendAttentionBackendImpl):
actual_seq_lengths=attn_metadata.prefill.chunked_context.
actual_chunk_seq_lengths)
batch_chunk_seq_mask = attn_metadata.prefill.chunked_context.batch_chunk_seq_mask
out_mask = batch_chunk_seq_mask[:, None, None].expand_as(
prefix_chunk_output)
prefix_chunk_output = torch.where(out_mask, 0, prefix_chunk_output)
lse_mask = batch_chunk_seq_mask[:, None,
None].expand_as(prefix_chunk_lse)
prefix_chunk_lse = torch.where(lse_mask, -torch.inf,
prefix_chunk_lse)
prefix_output, prefix_lse = self._update_chunk_attn_out_lse(
prefix_chunk_output, prefix_chunk_lse)
return prefix_output, prefix_lse
def _update_chunk_attn_out_lse(self, prefix_chunk_output,
prefix_chunk_lse):
# CP dimension all_gather and fusion
chunk_attn_out_lse = torch.cat([prefix_chunk_output, prefix_chunk_lse],
dim=-1)
if self.dcp_size > 1:
chunk_attn_out_lse = chunk_attn_out_lse.permute([1, 2,
0]).contiguous()
attn_out_lse_all2all = torch.empty_like(chunk_attn_out_lse)
dist.all_to_all_single(attn_out_lse_all2all,
chunk_attn_out_lse,
group=self.dcp_group)
chunk_attn_out_lse = attn_out_lse_all2all.permute([2, 0, 1])
if self.pcp_size > 1:
# AllGather out&lse within CP group
chunk_attn_out_lse = get_pcp_group().all_gather(
chunk_attn_out_lse.contiguous(), dim=0)
B_total, H_total, D_plus_1 = chunk_attn_out_lse.shape
S = B_total // self.pcp_size
H = H_total // self.dcp_size
D = self.head_size
assert D_plus_1 == D + 1
# [PCP, S, DCP, H, D+1]
x = chunk_attn_out_lse.view(self.pcp_size, S, self.dcp_size, H,
D_plus_1)
# [PCP, DCP, S, H, D+1]
x = x.permute(0, 2, 1, 3, 4).contiguous()
# Flatten [N, S, H, D+1], N = pcp_size * dcp_size
x = x.view(-1, S, H, D_plus_1)
# Split out lse.
# [N, S, H, D], [N, S, H, 1]
attn_out_allgather, attn_lse_allgather = torch.split(x, [D, 1], dim=-1)
prefix_output, prefix_lse = self._update_out_and_lse(
attn_out_allgather, attn_lse_allgather)
return prefix_output, prefix_lse
return prefix_chunk_output, prefix_chunk_lse
def _load_kv_for_chunk(self, attn_metadata, kv_cache,
local_chunked_kv_lens_rank, query, total_toks):
@@ -850,6 +802,45 @@ class AscendAttentionCPImpl(AscendAttentionBackendImpl):
return key, value
def _gather_global_context_output(self, local_context_attn_output):
if self.dcp_size > 1:
dcp_context_attn_output = torch.empty_like(
local_context_attn_output)
dist.all_to_all_single(dcp_context_attn_output,
local_context_attn_output,
group=self.dcp_group)
else:
dcp_context_attn_output = local_context_attn_output
if self.pcp_size > 1:
# AllGather out&lse within CP group
global_context_attn_output = get_pcp_group().all_gather(
dcp_context_attn_output, dim=-1)
else:
global_context_attn_output = dcp_context_attn_output
return global_context_attn_output
def _update_global_context_output(self, global_context_output):
B_total, H_total, D_plus_1 = global_context_output.shape
S = B_total // self.pcp_size
H = H_total // self.dcp_size
D = self.head_size
assert D_plus_1 == D + 1
# [PCP, S, DCP, H, D+1]
x = global_context_output.view(self.pcp_size, S, self.dcp_size, H,
D_plus_1)
# [PCP, DCP, S, H, D+1]
x = x.permute(0, 2, 1, 3, 4).contiguous()
# Flatten [N, S, H, D+1], N = pcp_size * dcp_size
x = x.view(-1, S, H, D_plus_1)
# Split out lse
attn_out_allgather, attn_lse_allgather = torch.split(
x, [D, 1], dim=-1) # [N, S, H, D], [N, S, H, 1]
context_output, context_lse = self._update_out_and_lse(
attn_out_allgather, attn_lse_allgather)
return context_output, context_lse
def forward_impl(
self,
query: torch.Tensor,
@@ -870,15 +861,38 @@ class AscendAttentionCPImpl(AscendAttentionBackendImpl):
output[:num_decode_tokens] = output_decode
if has_prefill:
assert attn_metadata.prefill is not None
# chunked prefill vars init
has_chunked_context = attn_metadata.prefill.chunked_context is not None
# Note(qcs): we use multi-stream for computation-communication overlap
# when enabling chunked prefill.
# current part
# current_stream: init -- pre -- head attn ------------------ tail attn -- post -- update
# context part -/
# current_stream: ----- -- context attn -- -/
# COMM_STREAM: \-- all_gather Q --/ \-- a2a ag output --/
# qkv init
num_actual_tokens_pcp_padded = attn_metadata.num_actual_tokens_pcp_padded // self.pcp_size
prefill_query = query[
num_decode_tokens:num_actual_tokens_pcp_padded].contiguous()
key = key[self.pcp_size * num_decode_tokens:].contiguous()
value = value[self.pcp_size * num_decode_tokens:].contiguous()
if has_chunked_context:
# all_gather q for chunked prefill // overlap the computation inner current chunk
cp_chunkedprefill_comm_stream().wait_stream(
torch.npu.current_stream())
with torch_npu.npu.stream(cp_chunkedprefill_comm_stream()):
prefill_query_all = self._prefill_query_all_gather(
attn_metadata, prefill_query.clone())
if self.pcp_size > 1:
# Scenario of Enabling PCP or PCP&DCP
attn_output_prefill, attn_lse_prefill = self._forward_prefill_cp(
# prepare qkv and compute the head part // overlap the communication of all gather q
data_head, data_tail = self._forward_prefill_cp_pre(
prefill_query, key, value, attn_metadata)
output_head, lse_head = self._forward_prefill_cp_attn(
data_head, True, attn_metadata)
else:
# Scenario of Enabling DCP Individually
attn_output_prefill, attn_lse_prefill = torch.ops.npu.npu_fused_infer_attention_score(
@@ -899,8 +913,46 @@ class AscendAttentionCPImpl(AscendAttentionBackendImpl):
actual_seq_lengths=attn_metadata.prefill.
actual_seq_lengths_q)
self._process_chunk_prefill(attn_output_prefill, attn_lse_prefill,
kv_cache, prefill_query, attn_metadata)
if has_chunked_context:
torch.npu.current_stream().wait_stream(
cp_chunkedprefill_comm_stream())
# computation of context
context_output = self._compute_prefill_context(
prefill_query_all, kv_cache, attn_metadata)
# Note(qcs): (output, lse) -> [Seq, Head_num, Head_dim+1] -> [Head_num, Head_dim+1, Seq]
local_context_output = torch.cat(
context_output, dim=-1).permute([1, 2, 0]).contiguous()
# all2all and all_gather output&lse // overlap the computation inner current chunk
cp_chunkedprefill_comm_stream().wait_stream(
torch.npu.current_stream())
with torch_npu.npu.stream(cp_chunkedprefill_comm_stream()):
global_context_output = self._gather_global_context_output(
local_context_output)
if self.pcp_size > 1:
# compute the tail part and reorg output&lse // overlap the communication of output
output_tail, lse_tail = self._forward_prefill_cp_attn(
data_tail, False, attn_metadata)
attn_output_prefill, attn_lse_prefill = self._forward_prefill_cp_post(
[output_head, output_tail],
[lse_head, lse_tail],
attn_metadata,
)
if attn_metadata.prefill is not None and attn_metadata.prefill.chunked_context is not None:
# update the output of current chunk with context part
torch.npu.current_stream().wait_stream(
cp_chunkedprefill_comm_stream())
global_context_output = global_context_output.permute(
[2, 0, 1]).contiguous()
context_output, context_lse = self._update_global_context_output(
global_context_output)
self._update_chunk_attn_out_lse_with_current_attn_out_lse(
attn_output_prefill, attn_lse_prefill, context_output,
context_lse, prefill_query, attn_metadata)
output[num_decode_tokens:attn_output_prefill.shape[0] +
num_decode_tokens] = attn_output_prefill
return output

1
vllm_ascend/attention/utils.py
View File

@@ -63,6 +63,7 @@ class AscendMetadataForPrefill:
cp_kv_recover_idx_for_chunk: Optional[list[int]] = None
kv_inverse_idx_for_chunk: Optional[list[int]] = None
batch_chunk_seq_mask: Optional[list[bool]] = None
local_total_toks: Optional[int] = None
""" Prefill Specific Metadata for Ascend"""
pcp_metadata: Optional[AscendPCPMetadata] = None

8
vllm_ascend/utils.py
View File

@@ -55,6 +55,7 @@ _PREFETCH_STREAM = None
_WEIGHT_PREFETCH_METHOD = None
_GLOBAL_STREAM = None
_SHARED_EXPERTS_CALCULATION_STREAM = None
_CP_CHUNKEDPREFILL_COMM_STREAM = None
_ASCEND_CUSTOMOP_IS_REIGISTERED = False
_DEFAULT_BUFFER_SIZE = 200
_MIN_DP_BUFFER_SIZE = 50
@@ -340,6 +341,13 @@ def shared_experts_calculation_stream() -> torch.npu.Stream:
return _SHARED_EXPERTS_CALCULATION_STREAM
def cp_chunkedprefill_comm_stream() -> torch.npu.Stream:
global _CP_CHUNKEDPREFILL_COMM_STREAM
if _CP_CHUNKEDPREFILL_COMM_STREAM is None:
_CP_CHUNKEDPREFILL_COMM_STREAM = torch_npu.npu.Stream()
return _CP_CHUNKEDPREFILL_COMM_STREAM
def adapt_patch(is_global_patch: bool = False):
if is_global_patch:
from vllm_ascend.patch import platform # noqa: F401

3
vllm_ascend/worker/model_runner_v1.py
View File

@@ -1771,9 +1771,6 @@ class NPUModelRunner(GPUModelRunner):
kv_cache_group_id].get_device_tensor()
slot_mapping = self.input_batch.block_table[
kv_cache_group_id].slot_mapping
self.cp_kv_recover_idx = torch.zeros(self.max_num_tokens,
dtype=torch.int32,
device=self.device)
long_seq_metadata = None if self.pcp_size * self.dcp_size == 1 else self.pcp_manager.generate_pcp_metadata(
num_tokens, self.query_lens, self.attn_mask,
self.input_batch)