Chengji Yao e9d6a3db69
[TPU] make ptxla not imported when using tpu_commons (#23081)
Signed-off-by: Chengji Yao <chengjiyao@gmail.com>
Signed-off-by: Chengji Yao <chengjiyao@google.com>
Co-authored-by: Chengji Yao <chengjiyao@gmail.com>
2025-08-19 11:46:42 +08:00

103 lines
4.2 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import os
from typing import Optional
import torch
from torch.distributed import ProcessGroup
from vllm.config import get_current_vllm_config
from vllm.logger import init_logger
from vllm.platforms import current_platform
from vllm.platforms.tpu import USE_TPU_COMMONS
from .base_device_communicator import DeviceCommunicatorBase
USE_RAY = parallel_config = get_current_vllm_config(
).parallel_config.distributed_executor_backend == "ray"
logger = init_logger(__name__)
if not USE_TPU_COMMONS:
logger.info("tpu_commons not found, using vLLM's TpuCommunicator")
if current_platform.is_tpu():
import torch_xla
import torch_xla.core.xla_model as xm
import torch_xla.runtime as xr
from torch_xla._internal import pjrt
from torch_xla.distributed.xla_multiprocessing import (
create_optimized_replica_groups)
if USE_RAY:
from vllm.executor import ray_utils
class TpuCommunicator(DeviceCommunicatorBase):
def __init__(self,
cpu_group: ProcessGroup,
device: Optional[torch.device] = None,
device_group: Optional[ProcessGroup] = None,
unique_name: str = ""):
super().__init__(cpu_group, device, device_group, unique_name)
# NOTE(woosuk): When using TP > 1 on TPUs, every TPU on the same node
# must be used together. Therefore, the local rank and world size can
# be simply calculated as follows.
global_rank = self.global_rank
global_world_size = self.global_world_size
if USE_RAY:
logger.info("TpuCommunicator initialized with RAY")
# Calculate how many TPU nodes are in the current deployment. This
# is the Ray placement group if it is deployed with Ray. Default
# to the number of TPU nodes in the Ray cluster. The number of TPU
# nodes is computed by the total number of TPUs divided by the
# number of TPU accelerators per node, to account for clusters
# with both CPUs and TPUs.
num_nodes = ray_utils.get_num_tpu_nodes()
num_nodes_in_pg = ray_utils.get_num_nodes_in_placement_group()
if num_nodes_in_pg > 0:
num_nodes = num_nodes_in_pg
local_world_size = global_world_size // num_nodes
local_rank = global_rank % local_world_size
else:
logger.info("TpuCommunicator initialized with MP")
# Sanity: Verify we run on a single host
num_hosts = torch_xla.tpu.num_tpu_workers()
assert num_hosts == 1
# Get the current number of TPUs (we have locally)
local_world_size = torch_xla.tpu.num_available_chips()
# Get current rank
local_rank = global_rank % local_world_size
# Ensure environment variables are set for multihost deployments.
# On GKE, this is needed for libtpu and TPU driver to know which TPU
# chip is actually visible. Otherwise the TPU driver will fail to
# initialize because the number of devices would be different from
# the number of visible worker addresses.
os.environ["CLOUD_TPU_TASK_ID"] = str(global_rank)
os.environ["TPU_VISIBLE_CHIPS"] = str(local_rank)
pjrt.initialize_multiprocess(local_rank, local_world_size)
xr._init_world_size_ordinal()
self.groups = create_optimized_replica_groups()
def all_reduce(self, input_: torch.Tensor) -> torch.Tensor:
# TODO: Remove the groups specification after XLA compiler can support
# auto-reordering the ring order for all-reduce.
return xm.all_reduce(xm.REDUCE_SUM, input_, groups=self.groups)
def all_gather(self, input_: torch.Tensor, dim: int = -1) -> torch.Tensor:
assert dim == -1, "TPUs only support dim=-1 for all-gather."
return xm.all_gather(input_, dim=dim)
if USE_TPU_COMMONS:
from tpu_commons.distributed.device_communicators import (
TpuCommunicator as TpuCommonsCommunicator)
TpuCommunicator = TpuCommonsCommunicator # type: ignore