Files
xc-llm-ascend/vllm_ascend/ops/fused_moe/moe_comm_method.py
weijinqian0 ae068a3342 [Refactor] remove moe type of multicast. (#4224)
The main purposes of this PR are as follows: 
1. Remove the multicast-related code; 

Reason:
1. In the scenario like a2 Dual-System Back-to-Back Networking,the
performance is worse than all_gather. Before the modification, in e2e
test, it was 3 tps; after the modification, it is 10 tps.
2. At the same time, we usually enable the SP feature,it is consistent
with the current logic.
3. The advantage of broadcast communication lies in the fact that it
does not suffer from uneven DP load and does not require the prefill ACL
graph to be enabled. But we support prefill Acl graph recently.

So we think there is no need to maintain the multicast as one choice in
moe communication.

Performance benefits are as follows:
When not enable_flashcomm1, TTFT remains relatively stable at around
43000ms, which is approximately 15000ms faster than before the
modification.

When enable_flashcomm1, there is no diffenence, TTFT remains relatively
stable at around 29000ms.


- vLLM version: v0.11.0
- vLLM main:
2918c1b49c

---------

Signed-off-by: weijinqian_v1 <weijinqian@huawei.com>
Signed-off-by: weijinqian0 <1184188277@qq.com>
Co-authored-by: weijinqian_v1 <weijinqian@huawei.com>
2025-11-24 17:32:37 +08:00

246 lines
11 KiB
Python

# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
# Copyright 2023 The vLLM team.
#
# 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.
# This file is a part of the vllm-ascend project.
from __future__ import annotations
from abc import ABC, abstractmethod
from typing import Any, Dict, Optional
import torch
from vllm.config import get_current_vllm_config
from vllm.forward_context import get_forward_context
from vllm.model_executor.layers.fused_moe import FusedMoEConfig
from vllm_ascend.ascend_forward_context import MoECommType
from vllm_ascend.ops.fused_moe.moe_mlp import unified_apply_mlp
from vllm_ascend.ops.fused_moe.prepare_finalize import (
PrepareAndFinalizeWithAll2All, PrepareAndFinalizeWithAllGather,
PrepareAndFinalizeWithMC2, QuantType)
from vllm_ascend.ops.fused_moe.token_dispatcher import (
TokenDispatcherWithAll2AllV, TokenDispatcherWithAllGather,
TokenDispatcherWithMC2, TokenDispatcherWithMoge)
_MoECommMethods: Dict[Optional[MoECommType], MoECommMethod] = {}
def get_moe_comm_method(
moe_comm_type: Optional[MoECommType]) -> Optional[MoECommMethod]:
return _MoECommMethods.get(moe_comm_type, None)
def setup_moe_comm_method(moe_config):
_MoECommMethods[MoECommType.ALLTOALL] = AlltoAllCommImpl(moe_config)
_MoECommMethods[MoECommType.ALLGATHER] = AllGatherCommImpl(moe_config)
_MoECommMethods[MoECommType.MC2] = MC2CommImpl(moe_config)
class MoECommMethod(ABC):
"""Base class for MoE communication methods."""
def __init__(self, moe_config: FusedMoEConfig):
self.model_type = get_current_vllm_config(
).model_config.hf_config.model_type
self.moe_config = moe_config
self.token_dispatcher = self._get_token_dispatcher()
self.prepare_finalize = self._get_prepare_finalize()
def prepare(
self,
hidden_states: torch.Tensor,
router_logits: torch.Tensor,
enable_shared_expert_dp: bool = False,
replace_allreduce: bool = False,
quant_type: QuantType = QuantType.NONE,
) -> tuple[torch.Tensor, torch.Tensor, Optional[torch.Tensor],
Optional[torch.Tensor]]:
hidden_states, router_logits, mc2_mask, context_metadata = self.prepare_finalize.prepare(
hidden_states, router_logits, enable_shared_expert_dp,
replace_allreduce, quant_type)
return hidden_states, router_logits, mc2_mask, context_metadata
def finalize(self,
hidden_states: torch.Tensor,
reduce_results: bool,
context_metadata: Optional[dict] = None) -> torch.Tensor:
hidden_states = self.prepare_finalize.finalize(hidden_states,
reduce_results,
context_metadata)
return hidden_states
def fused_experts(
self,
hidden_states: torch.Tensor,
w1: torch.Tensor,
w2: torch.Tensor,
topk_weights: torch.Tensor,
topk_ids: torch.Tensor,
activation: str = "silu",
apply_router_weight_on_input: bool = False,
use_int8_w8a8: bool = False,
use_int4_w4a8: bool = False,
global_num_experts: Optional[int] = None,
expert_map: Optional[torch.Tensor] = None,
w1_scale: Optional[torch.Tensor] = None,
w2_scale: Optional[torch.Tensor] = None,
w1_scale_bias: torch.Tensor = None,
w2_scale_bias: torch.Tensor = None,
# For TorchAir graph
is_torchair: bool = False,
# For Cube/Vector parallel
shared_experts: Optional[Any] = None,
quantized_x_for_share: Optional[Any] = None,
dynamic_scale_for_share: Optional[Any] = None,
# For load balance
log2phy: torch.Tensor = None,
global_redundant_expert_num: int = 0,
need_trans: bool = False,
dynamic_eplb: bool = False,
mc2_mask: torch.Tensor = None,
pertoken_scale: Optional[torch.Tensor] = None):
# Check constraints
assert hidden_states.dtype in [
torch.float32, torch.float16, torch.bfloat16, torch.int8
]
moe_comm_method = get_forward_context().moe_comm_method
assert moe_comm_method is not None, "Missing communication context"
results = self.token_dispatcher.token_dispatch(
hidden_states=hidden_states,
topk_weights=topk_weights,
topk_ids=topk_ids,
expert_map=expert_map,
log2phy=log2phy,
global_redundant_expert_num=global_redundant_expert_num,
shared_experts=shared_experts,
quantized_x_for_share=quantized_x_for_share,
dynamic_scale_for_share=dynamic_scale_for_share,
mc2_mask=mc2_mask,
apply_router_weight_on_input=apply_router_weight_on_input,
with_quant=use_int8_w8a8 or use_int4_w4a8,
dynamic_eplb=dynamic_eplb,
pertoken_scale=pertoken_scale)
permuted_hidden_states, expert_tokens, dynamic_scale, group_list_type, topk_scales, context_metadata = \
results["hidden_states"], results["group_list"], results.get("dynamic_scale"), results["group_list_type"], results.get("topk_scales"), results.get("context_metadata")
mlp_output = unified_apply_mlp(hidden_states=permuted_hidden_states,
w1=w1,
w1_scale=w1_scale,
w2=w2,
w2_scale=w2_scale,
group_list=expert_tokens,
dynamic_scale=dynamic_scale,
group_list_type=group_list_type,
w1_scale_bias=w1_scale_bias,
w2_scale_bias=w2_scale_bias,
topk_scales=topk_scales,
with_quant=use_int8_w8a8
or use_int4_w4a8,
fusion=use_int8_w8a8,
need_trans=need_trans,
dynamic_eplb=dynamic_eplb)
final_hidden_states = self.token_dispatcher.token_combine(
hidden_states=mlp_output, context_metadata=context_metadata)
if dynamic_eplb:
return (final_hidden_states, group_list_type, expert_tokens)
return final_hidden_states
@abstractmethod
def _get_token_dispatcher(self):
raise NotImplementedError(
"_get_token_dispatcher function not implemented.")
@abstractmethod
def _get_prepare_finalize(self):
raise NotImplementedError(
"_get_prepare_finalize function not implemented.")
class AllGatherCommImpl(MoECommMethod):
"""This implementation is the same as NativeAllGatherCommImpl,
but uses NPU-specific ops for better performance.
This implementation should be compatible with all scenarios, and
thus it is the default implementation for MoE communication methods.
It uses `torch_npu.npu_moe_init_routing_v2` for pre-processing
and `torch_npu.npu_moe_token_unpermute` for post-processing
to handle the token-to-expert mapping and communication efficiently.
NOTE(Yizhou): TBH, it is really weird that we were supposed to use
`torch_npu.npu_moe_init_routing_v2` and `torch_npu.npu_moe_finalize_routing`
or `torch_npu.npu_moe_token_permute` and `torch_npu.npu_moe_token_unpermute`
for pre-processing and post-processing, respectively.
But `npu_moe_finalize_routing` will lead to accuracy issues so we have to
use `torch_npu.npu_moe_token_unpermute` instead.
This is a workaround and should be removed after the issue is fixed.
"""
def _get_token_dispatcher(self):
if self.model_type == "PanguProMoE":
return TokenDispatcherWithMoge(
top_k=self.moe_config.experts_per_token,
num_experts=self.moe_config.num_experts,
num_local_experts=self.moe_config.num_local_experts)
else:
return TokenDispatcherWithAllGather(
top_k=self.moe_config.experts_per_token,
num_experts=self.moe_config.num_experts,
num_local_experts=self.moe_config.num_local_experts)
def _get_prepare_finalize(self):
return PrepareAndFinalizeWithAllGather(self.moe_config)
class MC2CommImpl(MoECommMethod):
"""This implementation is for the scenarios listed below:
1. `enable_expert_parallel=True`.
2. `npu_moe_distribute_dispatch` and `npu_moe_distribute_combine` are available.
3. `enable_expert_parallel=False` is not supported.
This implementation uses the MC2 communication method, which is optimized for
Communication and Computation parallelism on Ascend devices.
"""
def _get_token_dispatcher(self):
return TokenDispatcherWithMC2()
def _get_prepare_finalize(self):
return PrepareAndFinalizeWithMC2(self.moe_config)
class AlltoAllCommImpl(MoECommMethod):
"""This implementation is for the scenarios listed below:
1. `enable_expert_parallel=True`.
2. `npu_grouped_matmul` is available.
This implementation uses all-to-all communication to exchange tokens
between data parallel ranks before and after the MLP computation. It should
have better performance than AllGatherCommImpl when DP size > 1.
"""
def _get_token_dispatcher(self):
return TokenDispatcherWithAll2AllV(
top_k=self.moe_config.experts_per_token,
num_experts=self.moe_config.num_experts,
num_local_experts=self.moe_config.num_local_experts)
def _get_prepare_finalize(self):
return PrepareAndFinalizeWithAll2All(self.moe_config)