### What this PR does / why we need it?
For dense models, by not applying tensor parallelism (TP) to the
attention module and applying TP to the MLP module, the allreduce
operations in the attention module can be eliminated, thereby reducing
computational overhead. However, this approach increases memory usage,
so the environment variable VLLM_ASCEND_ENABLE_MLP_OPTIMZE is used to
control this optimization.
- vLLM main:
b17109beea
Signed-off-by: wangxiaoxin-sherie <wangxiaoxin7@huawei.com>
Co-authored-by: wangxiaoxin-sherie <wangxiaoxin7@huawei.com>
89 lines
2.9 KiB
Python
89 lines
2.9 KiB
Python
from typing import Optional
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import torch
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from vllm.config import ParallelConfig
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from vllm.distributed.parallel_state import (GroupCoordinator, get_world_group,
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init_model_parallel_group)
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import vllm_ascend.envs as envs_ascend
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# Currently, mc2 op need their own group coordinator.
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_MC2: Optional[GroupCoordinator] = None
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_MLP_TP: Optional[GroupCoordinator] = None
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def get_mc2_group() -> GroupCoordinator:
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assert _MC2 is not None, ("mc2 group is not initialized")
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return _MC2
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def get_mlp_tp_group() -> GroupCoordinator:
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assert _MLP_TP is not None, ("mlp group is not initialized")
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return _MLP_TP
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def model_parallel_initialized():
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return (_MC2 is not None)
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def init_ascend_model_parallel(parallel_config: ParallelConfig, ):
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if model_parallel_initialized():
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return
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assert torch.distributed.is_initialized()
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world_size = torch.distributed.get_world_size()
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backend = torch.distributed.get_backend(get_world_group().device_group)
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# The layout of all ranks: ExternalDP * EP
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# ExternalDP is the data parallel group that is not part of the model,
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# every dp rank can generate independently (in verl integration).
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all_ranks = torch.arange(world_size).reshape(
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-1, parallel_config.data_parallel_size *
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parallel_config.tensor_parallel_size)
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global _MC2
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group_ranks = all_ranks.unbind(0)
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group_ranks = [x.tolist() for x in group_ranks]
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_MC2 = init_model_parallel_group(group_ranks,
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get_world_group().local_rank,
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backend,
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group_name="mc2")
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if envs_ascend.VLLM_ASCEND_ENABLE_MLP_OPTIMIZE:
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global _MLP_TP
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assert _MLP_TP is None, (
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"mlp tensor model parallel group is already initialized")
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mlp_tp = parallel_config.data_parallel_size
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all_ranks_mlp_head = torch.arange(world_size).reshape(
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-1, mlp_tp, parallel_config.pipeline_parallel_size, 1) # noqa
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group_ranks = all_ranks_mlp_head.view(-1, mlp_tp).unbind(0)
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group_ranks = [x.tolist() for x in group_ranks]
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# message queue broadcaster is only used in tensor model parallel group
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_MLP_TP = init_model_parallel_group(group_ranks,
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get_world_group().local_rank,
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backend,
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group_name="mlp_tp")
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def get_mlp_tensor_model_parallel_world_size():
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"""Return world size for the tensor model parallel group."""
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return get_mlp_tp_group().world_size
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def get_mlp_tensor_model_parallel_rank():
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"""Return world size for the tensor model parallel group."""
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return get_mlp_tp_group().rank_in_group
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def destroy_ascend_model_parallel():
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global _MC2
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if _MC2:
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_MC2.destroy()
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_MC2 = None
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global _MLP_TP
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if _MLP_TP:
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_MLP_TP.destroy()
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_MLP_TP = None
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