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vllm-npu-plugin/vllm_npu/ops/moe/experts_selector.py
2026-02-10 23:08:39 +08:00

278 lines
11 KiB
Python

#
# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
# This file is a part of the vllm-ascend project.
#
# 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.
#
from typing import Callable, Optional
import torch
import torch_npu
from vllm.forward_context import get_forward_context
from vllm_npu.ascend_config import get_ascend_config
def select_experts(hidden_states: torch.Tensor,
router_logits: torch.Tensor,
top_k: int,
use_grouped_topk: bool,
renormalize: bool,
topk_group: Optional[int] = None,
num_expert_group: Optional[int] = None,
custom_routing_function: Optional[Callable] = None,
scoring_func: str = "softmax",
routed_scaling_factor=1.0,
e_score_correction_bias: Optional[torch.Tensor] = None,
indices_type: Optional[torch.dtype] = None,
global_num_experts: int = -1):
"""
Fused experts with select experts.
Args:
router_logits: router logits of shape (num_tokens, hidden_size).
hidden_states: Hidden states of shape (num_tokens, hidden_size).
top_k: number of top k experts.
use_grouped_topk: Whether to group experts before selecting top-k.
renormalize: Whether to renormalize the routing weights.
topk_group: Number of expert groups to select from.
num_expert_group: Number of experts in each group.
custom_routing_function: Custom routing function.
scoring_func: Scoring function to use.
e_score_correction_bias: Correction bias to apply to expert scores.
indices_type: dtype of indices
global_num_experts: Global number of experts.
Returns:
topk_weights: router weights of shape (num_tokens, top_k).
topk_ids: selected expert IDs of shape (num_tokens, top_k).
"""
# prefetch w1_w3_proj.weight preprocess
weight_prefetch_method = get_forward_context().weight_prefetch_method
if weight_prefetch_method:
weight_prefetch_method.maybe_prefetch_moe_weight_preprocess(
hidden_states, "gate_up")
topk_weights, topk_ids = _select_experts_with_fusion_ops(
hidden_states=hidden_states,
router_logits=router_logits,
top_k=top_k,
use_grouped_topk=use_grouped_topk,
topk_group=topk_group,
renormalize=renormalize,
e_score_correction_bias=e_score_correction_bias,
num_expert_group=num_expert_group,
custom_routing_function=custom_routing_function,
scoring_func=scoring_func,
routed_scaling_factor=routed_scaling_factor,
global_num_experts=global_num_experts)
if topk_weights is None:
topk_weights, topk_ids = _native_select_experts(
hidden_states=hidden_states,
router_logits=router_logits,
top_k=top_k,
use_grouped_topk=use_grouped_topk,
renormalize=renormalize,
topk_group=topk_group,
num_expert_group=num_expert_group,
custom_routing_function=custom_routing_function,
scoring_func=scoring_func,
e_score_correction_bias=e_score_correction_bias,
global_num_experts=global_num_experts,
)
return topk_weights, topk_ids
def _native_grouped_topk(
topk_weights: torch.Tensor,
num_expert_group: Optional[int],
topk_group: Optional[int],
):
topk_group = 0 if topk_group is None else topk_group
num_expert_group = 0 if num_expert_group is None else num_expert_group
num_token = topk_weights.shape[0]
grouped_weights = topk_weights.view(num_token, num_expert_group,
-1).max(dim=-1).values
topk_group_indices = torch.topk(grouped_weights.to(torch.float32),
k=topk_group,
dim=-1,
sorted=False)[1]
topk_group_mask = torch.zeros_like(grouped_weights)
topk_group_mask.scatter_(1, topk_group_indices, 1)
topk_weight_mask = (topk_group_mask.unsqueeze(-1).expand(
num_token, num_expert_group,
topk_weights.shape[-1] // num_expert_group).reshape(num_token, -1))
topk_weights = topk_weights.masked_fill(~topk_weight_mask.bool(), 0.0)
return topk_weights
def _renormalize_topk_weights(
topk_weights: torch.Tensor,
renormalize: bool,
):
if renormalize:
topk_weights = topk_weights / topk_weights.sum(dim=-1, keepdim=True)
return topk_weights
def _select_expert_use_group_topk(
topk_weights: torch.Tensor, topk_group: Optional[int],
renormalize: bool, top_k: int, num_expert_group: Optional[int],
e_score_correction_bias: Optional[torch.Tensor]):
assert topk_group is not None
assert num_expert_group is not None
if e_score_correction_bias is not None:
# Store original scores before applying correction bias. We use biased
# scores for expert selection but original scores for routing weights
original_weights = topk_weights
topk_weights = topk_weights + e_score_correction_bias.unsqueeze(0)
# TODO: Change to npu_group_topk when the latest CANN and NNAL is available
# >>> torch_npu._npu_group_topk(topk_weights, group_num=num_expert_group, k=topk_group)
topk_weights = _native_grouped_topk(topk_weights, num_expert_group,
topk_group)
# TODO bfloat16 is not supported in torch.topk with ge graph.
if e_score_correction_bias is not None:
topk_ids = torch.topk(topk_weights.to(torch.float32),
k=top_k,
dim=-1,
sorted=False)[1]
# Use original unbiased scores for the routing weights
topk_weights = original_weights.gather(1, topk_ids)
else:
topk_weights, topk_ids = torch.topk(topk_weights.to(torch.float32),
k=top_k,
dim=-1,
sorted=False)
topk_ids = topk_ids.to(torch.int32)
topk_weights = _renormalize_topk_weights(topk_weights, renormalize)
return topk_weights, topk_ids
def _select_experts_with_fusion_ops(
hidden_states: torch.Tensor,
router_logits: torch.Tensor,
top_k: int,
use_grouped_topk: bool,
renormalize: bool,
e_score_correction_bias: Optional[torch.Tensor],
topk_group: Optional[int],
num_expert_group: Optional[int],
custom_routing_function: Optional[Callable] = None,
scoring_func: str = "softmax",
routed_scaling_factor=1.0,
global_num_experts: int = -1):
topk_weights, topk_ids = None, None
# NOTE: now npu_moe_gating_top_k can only support 'group_count=256' pattern
global_redundant_expert_num = get_ascend_config().init_redundancy_expert
is_deepseek_v3_r1 = global_num_experts - global_redundant_expert_num == 256
if is_deepseek_v3_r1:
topk_weights, topk_ids, _ = torch_npu.npu_moe_gating_top_k(
router_logits,
k=top_k, # topk currently 8
bias=e_score_correction_bias,
k_group=topk_group, # fix: 4
group_count=num_expert_group, # fix 8
group_select_mode=
1, # 0: the maximum in the group; 1: topk2.sum(fix)
renorm=0, # 0: softmax->topk(fix); 1: topk->softmax
norm_type=1, # 0: softmax; 1: sigmoid(fix)
# out_flag=False, # todo new api; should the third output be output
# y2_flag=False, # old api; should the third output be output
routed_scaling_factor=1,
eps=float(1e-20))
if not use_grouped_topk and custom_routing_function is None and scoring_func == "softmax":
topk_weights, topk_ids, _ = torch_npu.npu_moe_gating_top_k_softmax(
x=router_logits, finished=None, k=top_k)
topk_ids = topk_ids.to(torch.int32)
topk_weights = _renormalize_topk_weights(topk_weights, renormalize)
return topk_weights, topk_ids
def _native_select_experts(
hidden_states: torch.Tensor,
router_logits: torch.Tensor,
top_k: int,
use_grouped_topk: bool,
renormalize: bool,
topk_group: Optional[int] = None,
num_expert_group: Optional[int] = None,
custom_routing_function: Optional[Callable] = None,
scoring_func: str = "softmax",
e_score_correction_bias: Optional[torch.Tensor] = None,
global_num_experts: Optional[torch.Tensor] = None
) -> tuple[torch.Tensor, torch.Tensor]:
"""
Select top-k experts based on router logits.
Args:
hidden_states: Hidden states of shape (num_tokens, hidden_size).
router_logits: Router logits of shape (num_tokens, num_experts).
top_k: Number of experts to select.
use_grouped_topk: Whether to group experts before selecting top-k.
renormalize: Whether to renormalize the routing weights.
topk_group: Number of expert groups to select from.
num_expert_group: Number of experts in each group.
custom_routing_function: Custom routing function.
scoring_func: Scoring function to use.
e_score_correction_bias: Correction bias to apply to expert scores.
Returns:
topk_weights: Routing weights of shape (num_tokens, top_k).
topk_ids: Selected expert IDs of shape (num_tokens, top_k).
Raises:
ValueError: If an unsupported scoring function is provided.
"""
if scoring_func == "softmax":
topk_weights = router_logits.softmax(dim=-1)
elif scoring_func == "sigmoid":
topk_weights = router_logits.sigmoid()
else:
raise ValueError(f"Unsupported scoring function: {scoring_func}")
if use_grouped_topk:
return _select_expert_use_group_topk(
topk_weights=topk_weights,
top_k=top_k,
renormalize=renormalize,
topk_group=topk_group,
num_expert_group=num_expert_group,
e_score_correction_bias=e_score_correction_bias)
if custom_routing_function is not None:
topk_weights, topk_ids = custom_routing_function(
hidden_states=hidden_states,
gating_output=router_logits,
topk=top_k,
renormalize=renormalize,
global_num_experts=global_num_experts)
# Required by npu_moe_init_routing
topk_ids = topk_ids.to(torch.int32)
return topk_weights, topk_ids
topk_weights, topk_ids = topk_weights.topk(top_k, dim=-1)
topk_weights = topk_weights.to(hidden_states.dtype)
# Required by npu_moe_init_routing
topk_ids = topk_ids.to(torch.int32)
topk_weights = _renormalize_topk_weights(topk_weights, renormalize)
return topk_weights, topk_ids