Files
xc-llm-ascend/vllm_ascend/attention/attention_mask.py
LICO67373 380f089fbf [Refactor] Fix AttentionMaskBuilder singleton and remove redundant pcp_prefill_mask (#4870)
## What this PR does / why we need it?

This PR fixes the `AttentionMaskBuilder` singleton initialization issue
introduced in PR #4779 and removes the unused `pcp_prefill_mask` field.

### Background

After PR #4779 made `AttentionMaskBuilder` a singleton with `@singleton`
decorator, the class constructor now requires a `device` parameter.
However, two initialization sites were still using the old parameterless
constructor, causing failures.

### Changes

1. **Fix singleton initialization**
- Fixed `AttentionMaskBuilder()` → `AttentionMaskBuilder(self.device)`
in `AscendMLAMetadataBuilder.__init__()`
- Fixed `AttentionMaskBuilder()` → `AttentionMaskBuilder(self.device)`
in `AscendAttentionMetadataBuilder.__init__()`

2. **Remove unused field**
- Removed `pcp_prefill_mask` field from
`AscendPrefillContextParallelMetadata` (never used in codebase)
   - Updated related test assertions

### Related

- Issue #5463
- PR #4779 (Unify all mask generation methods)
- PR #5389 (Make AttentionMaskBuilder singleton)

## Does this PR introduce _any_ user-facing change?

No. This is an internal refactoring.

## How was this patch tested?

-  Local testing: No linter errors
-  Unit tests for attention modules verified
-  CI pipeline

Signed-off-by: lico67373 <918688502@qq.com>
Co-authored-by: weijinqian0 <1184188277@qq.com>
2026-01-07 17:09:52 +08:00

102 lines
4.3 KiB
Python

#
# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import torch
from vllm.distributed import get_pcp_group
from vllm_ascend.platform import ModelConfig
from vllm_ascend.utils import singleton
def _generate_attn_mask(max_seq_len, dtype):
# Construct lower triangle matrix.
mask_flag = torch.ones((max_seq_len, max_seq_len),
dtype=torch.bool).tril_()
# Create upper triangle matrix used to mark mask positions.
mask_flag = ~mask_flag
# Currently for fp16 dtype, the mask value should be set to -inf.
# TODO: Eliminate this part in the future.
mask_value = float('-inf') if dtype == torch.float16 else 1
attn_mask = torch.zeros(size=(max_seq_len, max_seq_len), dtype=dtype) \
.masked_fill_(mask_flag, mask_value)
return attn_mask
@singleton
class AttentionMaskBuilder:
def __init__(self, device: torch.device):
self.attn_mask_cache = None
self._seq_len_cached = 0
self.device = device
self.mla_mask = None
self.chunked_prefill_attn_mask = None
self.pcp_mla_mask = None
self.swa_mask = None
def get_attn_mask(self, max_seq_len: int, dtype: torch.dtype):
if self.attn_mask_cache is None or max_seq_len > self._seq_len_cached:
self.attn_mask_cache = _generate_attn_mask(max_seq_len, dtype)
self._seq_len_cached = max_seq_len
assert self.attn_mask_cache is not None, "Something is wrong in generate_attn_mask."
if self.attn_mask_cache.dtype != dtype:
self.attn_mask_cache = self.attn_mask_cache.to(dtype)
return self.attn_mask_cache[:max_seq_len, :max_seq_len].contiguous(
).to(self.device, non_blocking=True)
def get_splitfuse_attn_mask(self) -> torch.Tensor:
if self.chunked_prefill_attn_mask is None:
self.chunked_prefill_attn_mask = torch.triu(
torch.ones(2048,
2048), diagonal=1).to(torch.int8).to(self.device)
return self.chunked_prefill_attn_mask
def get_mla_mask(self, dtype: torch.dtype) -> torch.Tensor:
if self.mla_mask is None or self.mla_mask.dtype != dtype:
if dtype == torch.float16:
mask_value = torch.finfo(torch.float32).min
else:
mask_value = 1
prefill_mask = torch.triu(
torch.ones(512, 512, device=self.device, dtype=dtype), 1)
self.mla_mask = torch.where(prefill_mask == 1, mask_value,
0).to(dtype)
return self.mla_mask
def get_pcp_mla_mask(self, dtype: torch.dtype):
if self.pcp_mla_mask is None or self.pcp_mla_mask.dtype != dtype:
self.pcp_mla_mask = torch.triu(
torch.ones(512, 512, device=self.device, dtype=dtype), 1)
return self.pcp_mla_mask
def get_swa_mask(self, dtype: torch.dtype, sliding_window):
if self.swa_mask is None or self.swa_mask.dtype != dtype:
if sliding_window is not None:
mask = torch.ones(2048, 2048, dtype=torch.bool)
triu_mask = torch.triu(mask, diagonal=1).to(self.device)
tril_mask = torch.tril(mask, -sliding_window).to(self.device)
self.swa_mask = triu_mask + tril_mask
return self.swa_mask
def get_attention_mask(self, model_config: ModelConfig):
if model_config.runner_type == "pooling":
return self.get_attn_mask(2048, torch.bool)
return self.get_splitfuse_attn_mask()
def get_final_mla_mask(self, model_config: ModelConfig):
if get_pcp_group().world_size > 1:
return self.get_pcp_mla_mask(model_config.dtype)
# Prefill stages use 512x512 mask with appropriate dtype
return self.get_mla_mask(model_config.dtype)