Files
vLLM/vllm/distributed/device_communicators/all2all.py
T

127 lines
4.6 KiB
Python

# SPDX-License-Identifier: Apache-2.0
import importlib.util
from typing import TYPE_CHECKING
import torch
import torch.distributed as dist
from vllm.forward_context import get_forward_context
from vllm.logger import init_logger
from .base_device_communicator import All2AllManagerBase, Cache
logger = init_logger(__name__)
if TYPE_CHECKING:
from vllm.model_executor.layers.fused_moe.layer import FusedMoE
else:
FusedMoE = None
class NaiveAll2AllManager(All2AllManagerBase):
"""
A naive implementation of all2all communication.
It uses all-reduce under the hood, which is not
efficient at all. The main purpose is for testing and
debugging.
"""
def __init__(self, cpu_group):
super().__init__(cpu_group)
def naive_multicast(self, x: torch.Tensor,
cu_tokens_across_dp_cpu: torch.Tensor):
assert (len(x.shape) == 2)
buffer = torch.empty((cu_tokens_across_dp_cpu[-1], x.size(1)),
device=x.device,
dtype=x.dtype)
start = 0 if self.dp_rank == 0 else cu_tokens_across_dp_cpu[
self.dp_rank - 1]
end = cu_tokens_across_dp_cpu[self.dp_rank]
buffer[start:end, :].copy_(x)
for idx in range(self.dp_world_size):
start = 0 if idx == 0 else cu_tokens_across_dp_cpu[idx - 1]
end = cu_tokens_across_dp_cpu[idx]
self.dp_group.broadcast(buffer[start:end, :], idx)
return buffer
def dispatch(self, hidden_states: torch.Tensor,
router_logits: torch.Tensor):
cu_tokens_across_dp_cpu = get_forward_context(
).dp_metadata.cu_tokens_across_dp_cpu
hidden_states = self.naive_multicast(hidden_states,
cu_tokens_across_dp_cpu)
router_logits = self.naive_multicast(router_logits,
cu_tokens_across_dp_cpu)
return hidden_states, router_logits
def combine(self, hidden_states: torch.Tensor) -> torch.Tensor:
cu_tokens_across_dp_cpu = get_forward_context(
).dp_metadata.cu_tokens_across_dp_cpu
start = 0 if self.dp_rank == 0 else cu_tokens_across_dp_cpu[
self.dp_rank - 1]
end = cu_tokens_across_dp_cpu[self.dp_rank]
all_hidden_states = self.dp_group.all_reduce(hidden_states)
hidden_states = all_hidden_states[start:end, :]
return hidden_states
def destroy(self):
pass
class PPLXAll2AllManager(All2AllManagerBase):
"""
All2All communication based on PPLX kernels.
"""
def __init__(self, cpu_group):
has_pplx = importlib.util.find_spec("pplx_kernels") is not None
assert has_pplx, "pplx_kernels not found. Please follow https://github.com/vllm-project/vllm/blob/main/tools/ep_kernels/README.md to install pplx_kernels." # noqa
super().__init__(cpu_group)
if self.internode:
# inter-node communication needs nvshmem,
# intra-node communication uses p2p mapping directly
from pplx_kernels.nvshmem import (nvshmem_alloc_empty_unique_id,
nvshmem_get_unique_id,
nvshmem_init)
logger.debug(
"Initialize NVSHMEM for pplx_kernels: "
"rank=%d, world size=%d", self.rank, self.world_size)
uid = nvshmem_get_unique_id(
) if self.rank == 0 else nvshmem_alloc_empty_unique_id()
dist.broadcast(uid,
src=dist.get_process_group_ranks(self.cpu_group)[0],
group=self.cpu_group)
logger.debug("PPLX NVSHMEM UID = %s", uid)
nvshmem_init(uid, self.rank, self.world_size)
self.handle_cache = Cache()
def get_handle(self, kwargs):
import pplx_kernels as pplx
return self.handle_cache.get_or_create(
kwargs, pplx.AllToAll.internode
if self.internode else pplx.AllToAll.intranode)
def dispatch(self, hidden_states: torch.Tensor,
router_logits: torch.Tensor):
raise NotImplementedError
def combine(self, hidden_states: torch.Tensor) -> torch.Tensor:
raise NotImplementedError
def destroy(self):
with self.handle_cache._lock:
for _, handle in self.handle_cache._cache.items():
handle.destroy()
if self.internode:
from pplx_kernels.nvshmem import nvshmem_finalize
logger.debug("PPLX NVSHMEM finalize")
nvshmem_finalize()