Source code for lightning.fabric.plugins.environments.mpi
# Copyright The Lightning AI 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.
import logging
import socket
from functools import lru_cache
from typing import Optional
import numpy as np
from lightning_utilities.core.imports import RequirementCache
from lightning.fabric.plugins.environments.cluster_environment import ClusterEnvironment
from lightning.fabric.plugins.environments.lightning import find_free_network_port
log = logging.getLogger(__name__)
_MPI4PY_AVAILABLE = RequirementCache("mpi4py")
[docs]class MPIEnvironment(ClusterEnvironment):
"""An environment for running on clusters with processes created through MPI.
Requires the installation of the `mpi4py` package. See also: https://github.com/mpi4py/mpi4py
"""
def __init__(self) -> None:
if not _MPI4PY_AVAILABLE:
raise ModuleNotFoundError(str(_MPI4PY_AVAILABLE))
from mpi4py import MPI
self._comm_world = MPI.COMM_WORLD
self._comm_local: Optional[MPI.Comm] = None
self._node_rank: Optional[int] = None
self._main_address: Optional[str] = None
self._main_port: Optional[int] = None
@property
def creates_processes_externally(self) -> bool:
return True
@property
def main_address(self) -> str:
if self._main_address is None:
self._main_address = self._get_main_address()
return self._main_address
@property
def main_port(self) -> int:
if self._main_port is None:
self._main_port = self._get_main_port()
return self._main_port
[docs] @staticmethod
def detect() -> bool:
"""Returns ``True`` if the `mpi4py` package is installed and MPI returns a world size greater than 1."""
if not _MPI4PY_AVAILABLE:
return False
from mpi4py import MPI
return MPI.COMM_WORLD.Get_size() > 1
def set_world_size(self, size: int) -> None:
log.debug("MPIEnvironment.set_world_size was called, but setting world size is not allowed. Ignored.")
def set_global_rank(self, rank: int) -> None:
log.debug("MPIEnvironment.set_global_rank was called, but setting global rank is not allowed. Ignored.")
[docs] @lru_cache(1)
def local_rank(self) -> int:
if self._comm_local is None:
self._init_comm_local()
assert self._comm_local is not None
return self._comm_local.Get_rank()
[docs] def node_rank(self) -> int:
if self._node_rank is None:
self._init_comm_local()
assert self._node_rank is not None
return self._node_rank
def _get_main_address(self) -> str:
return self._comm_world.bcast(socket.gethostname(), root=0)
def _get_main_port(self) -> int:
return self._comm_world.bcast(find_free_network_port(), root=0)
def _init_comm_local(self) -> None:
hostname = socket.gethostname()
all_hostnames = self._comm_world.gather(hostname, root=0)
# sort all the hostnames, and find unique ones
unique_hosts = np.unique(all_hostnames)
unique_hosts = self._comm_world.bcast(unique_hosts, root=0)
# find the integer for this host in the list of hosts:
self._node_rank = int(np.where(unique_hosts == hostname)[0])
self._comm_local = self._comm_world.Split(color=self._node_rank)