Files
xc-llm-ascend/tests/e2e/multicard/moe/test_moe_comm.py
yiz-liu a6bb502e70 [2/N][Feat] Add MC2 communication method for MoE layers (#2469)
### What this PR does / why we need it?
This method replaces the previous all-gather approach for small numbers
of tokens.

The key changes include:
- A new `AscendFusedMoE` layer that handles token splitting, local
computation, and final aggregation via all-gather.
- Logic in the model runner to dynamically select between the new MC2
method and the existing all-gather method based on the number of input
tokens.
- Sharding the MoE communication mask across tensor-parallel ranks.

### Does this PR introduce _any_ user-facing change?
None.

### How was this patch tested?
Test case fixed.


- vLLM version: v0.10.1.1
- vLLM main:
b00e69f8ca

---------

Signed-off-by: Yizhou Liu <liu_yizhou@outlook.com>
2025-08-26 19:05:23 +08:00

168 lines
6.3 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 types import SimpleNamespace
import pytest
import torch
from vllm.model_executor.layers.fused_moe.config import ( # isort: skip
FusedMoEConfig, FusedMoEParallelConfig)
from vllm_ascend.distributed.moe_comm_method import ( # isort: skip
AllGatherCommImpl, NativeAllGatherCommImpl)
@pytest.mark.parametrize("num_tokens", [16, 128])
@pytest.mark.parametrize("hidden_size", [64, 128])
@pytest.mark.parametrize("global_num_experts", [8, 16])
@pytest.mark.parametrize("num_local_experts", [4, 8])
@pytest.mark.parametrize("top_k_num", [2, 4])
@pytest.mark.parametrize("dtype", [torch.bfloat16, torch.float16])
@pytest.mark.parametrize("ep_rank", [0, 1])
def test_all_gather_comm_impl(
num_tokens,
hidden_size,
global_num_experts,
num_local_experts,
top_k_num,
dtype,
ep_rank,
mocker,
):
"""
Tests the AllGatherCommImpl against the NativeAllGatherCommImpl.
This test compares the outputs of the NPU-optimized AllGatherCommImpl
with a native PyTorch implementation (NativeAllGatherCommImpl) to ensure
correctness across various configurations.
"""
if top_k_num > global_num_experts:
pytest.skip("top_k_num cannot be greater than global_num_experts")
if num_local_experts > global_num_experts:
pytest.skip(
"num_local_experts cannot be greater than global_num_experts")
device = torch.device("npu")
# mock get_tensor_model_parallel_rank to return ep_rank
mocker.patch(
"vllm.model_executor.layers.fused_moe.config.get_tensor_model_parallel_rank",
return_value=ep_rank,
)
# make moe config
parallel_config = SimpleNamespace(
enable_expert_parallel=num_local_experts < global_num_experts)
moe_parallel_config: FusedMoEParallelConfig = FusedMoEParallelConfig.make(
tp_size_=max(2, global_num_experts // num_local_experts),
dp_size_=1,
vllm_parallel_config=parallel_config,
)
moe_config = FusedMoEConfig(
num_experts=global_num_experts,
experts_per_token=top_k_num,
hidden_dim=hidden_size,
num_local_experts=num_local_experts,
moe_parallel_config=moe_parallel_config,
in_dtype=dtype,
quant_config=None, # No quantization in this test
max_num_tokens=num_tokens,
)
# Instantiate implementations
native_impl = NativeAllGatherCommImpl(moe_config)
all_gather_impl = AllGatherCommImpl(moe_config)
# --- Input Data ---
hidden_states = torch.randn(num_tokens,
hidden_size,
device=device,
dtype=dtype)
topk_ids = torch.randint(0,
global_num_experts, (num_tokens, top_k_num),
device=device,
dtype=torch.int32)
topk_weights = torch.rand(num_tokens, top_k_num, device=device).to(dtype)
topk_weights = torch.nn.functional.softmax(topk_weights, dim=1)
num_experts = global_num_experts
expert_map = None
if num_local_experts < global_num_experts:
# Create a map where some experts are local and some are not
expert_map = torch.full((global_num_experts, ), -1, device=device)
expert_map[ep_rank * num_local_experts:(ep_rank + 1) *
num_local_experts] = torch.arange(num_local_experts,
device=device)
num_experts = num_local_experts
# --- Run Native Implementation (Golden Reference) ---
native_hidden_states_out = hidden_states.clone()
(
native_permuted_hidden,
native_expert_tokens,
_,
) = native_impl.permute(hidden_states, topk_ids, topk_weights, expert_map,
num_experts)
# Simulate MLP output
native_mlp_output = torch.randn_like(native_permuted_hidden)
native_impl.unpermute(native_mlp_output, native_hidden_states_out)
# --- Run AllGather Implementation ---
all_gather_hidden_states_out = hidden_states.clone()
(
all_gather_permuted_hidden,
all_gather_expert_tokens,
_,
) = all_gather_impl.permute(hidden_states, topk_ids, topk_weights,
expert_map, num_experts)
# Use the same simulated MLP output for a fair comparison
all_gather_mlp_output = native_mlp_output.clone()
all_gather_impl.unpermute(all_gather_mlp_output,
all_gather_hidden_states_out)
# --- Assertions ---
# Define tolerance based on dtype
atol = 1e-3 if dtype == torch.float16 else 1e-2
rtol = 1e-3 if dtype == torch.float16 else 1e-2
# 1. Compare expert_tokens from pre_process
assert torch.allclose(native_expert_tokens.to(
all_gather_expert_tokens.device),
all_gather_expert_tokens,
atol=atol,
rtol=rtol), "Expert tokens do not match."
# 2. Compare permuted_hidden_states from pre_process
num_valid_tokens = native_expert_tokens.sum()
assert torch.allclose(native_permuted_hidden[:num_valid_tokens].to(
all_gather_permuted_hidden.device),
all_gather_permuted_hidden[:num_valid_tokens],
atol=atol,
rtol=rtol), "Permuted hidden states do not match."
# 3. Compare final hidden_states from post_process
assert torch.allclose(native_hidden_states_out.to(
all_gather_hidden_states_out.device),
all_gather_hidden_states_out,
atol=atol,
rtol=rtol), "Final hidden states do not match."