Files
AstrAI/astrai/parallel/setup.py
T

282 lines
7.4 KiB
Python

import logging
import os
import signal
import socket
import threading
from abc import ABC, abstractmethod
from contextlib import contextmanager
from functools import wraps
from typing import Callable, Optional
import torch
import torch.distributed as dist
import torch.multiprocessing as mp
from astrai.signal_handler import install_early_signal_handlers
logger = logging.getLogger(__name__)
def find_free_port() -> str:
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.bind(("", 0))
return str(s.getsockname()[1])
def get_current_device():
return os.environ["LOCAL_DEVICE"]
def get_world_size() -> int:
if dist.is_available() and dist.is_initialized():
return dist.get_world_size()
else:
return 1
def get_rank() -> int:
if dist.is_available() and dist.is_initialized():
return dist.get_rank()
else:
return 0
@contextmanager
def setup_parallel(
rank: int,
world_size: int,
local_rank: int,
backend: str = "nccl",
master_addr: str = "localhost",
master_port: str = "29500",
device_type: str = "cuda",
):
if dist.is_available() and dist.is_initialized():
yield dist.group.WORLD
return
if world_size <= 1:
device_id = torch.device(device_type, local_rank)
os.environ["LOCAL_RANK"] = str(local_rank)
os.environ["WORLD_SIZE"] = "1"
os.environ["LOCAL_DEVICE"] = str(device_id)
yield None
return
device_id = torch.device(device_type, local_rank)
os.environ["MASTER_ADDR"] = master_addr
os.environ["MASTER_PORT"] = master_port
os.environ["LOCAL_RANK"] = str(local_rank)
os.environ["WORLD_SIZE"] = str(world_size)
os.environ["LOCAL_DEVICE"] = str(device_id)
pg_kwargs = dict(rank=rank, world_size=world_size, backend=backend)
if backend in ("nccl", "ccl"):
pg_kwargs["device_id"] = device_id
dist.init_process_group(**pg_kwargs)
try:
if backend == "nccl" and torch.cuda.is_available():
torch.cuda.set_device(device_id)
elif backend == "ccl" and hasattr(torch, "xpu") and torch.xpu.is_available():
torch.xpu.set_device(device_id)
yield dist.group.WORLD
finally:
if dist.is_initialized():
dist.destroy_process_group()
def only_on_rank(rank, sync=False):
"""
decorator to run a function only on a specific rank.
"""
def decorator(func):
@wraps(func)
def wrapper(*args, **kwargs):
ret_args = None
if get_rank() == rank:
ret_args = func(*args, **kwargs)
if sync and dist.is_available() and dist.is_initialized():
dist.barrier()
return ret_args
return wrapper
return decorator
def _run_single_rank(
rank: int,
world_size: int,
backend: str,
master_addr: str,
master_port: str,
device_type: str,
func: Callable,
kwargs: dict,
):
install_early_signal_handlers()
with setup_parallel(
rank=rank,
world_size=world_size,
local_rank=rank,
backend=backend,
master_addr=master_addr,
master_port=master_port,
device_type=device_type,
):
func(**kwargs)
class LaunchStrategy(ABC):
"""Strategy for launching a function in a distributed context."""
def __init__(
self,
world_size: int,
backend: str,
master_addr: str,
master_port: str,
device_type: str,
start_method: str,
):
self.world_size = world_size
self.backend = backend
self.master_addr = master_addr
self.master_port = master_port
self.device_type = device_type
self.start_method = start_method
@abstractmethod
def launch(self, func: Callable, **kwargs):
raise NotImplementedError
class TorchrunStrategy(LaunchStrategy):
"""External orchestrator (torchrun, SLURM, K8s) — env vars pre-set."""
def launch(self, func: Callable, **kwargs):
install_early_signal_handlers()
rank = int(os.environ["RANK"])
world_size = int(os.environ["WORLD_SIZE"])
local_rank = int(os.environ.get("LOCAL_RANK", rank))
with setup_parallel(
rank=rank,
world_size=world_size,
local_rank=local_rank,
backend=self.backend,
master_addr=os.environ.get("MASTER_ADDR", self.master_addr),
master_port=os.environ.get("MASTER_PORT", self.master_port),
device_type=self.device_type,
):
func(**kwargs)
class LocalStrategy(LaunchStrategy):
"""Local launcher — single-process or mp.start_processes."""
def launch(self, func: Callable, **kwargs):
args = (
self.world_size,
self.backend,
self.master_addr,
self.master_port,
self.device_type,
func,
kwargs,
)
if self.world_size == 1:
_run_single_rank(0, *args)
return
install_early_signal_handlers()
ctx = mp.start_processes(
_run_single_rank,
args=args,
nprocs=self.world_size,
start_method=self.start_method,
join=False,
)
parent_stop = threading.Event()
original_handlers = {}
def _parent_handler(signum, frame):
sig = signal.Signals(signum)
logger.warning(
"Parent (pid=%d) received %s, forwarding to children...",
os.getpid(),
sig.name,
)
parent_stop.set()
for p in ctx.processes:
if p.is_alive():
p.terminate()
for sig in (signal.SIGTERM, signal.SIGINT):
prev = signal.signal(sig, _parent_handler)
if prev not in (signal.SIG_DFL, signal.SIG_IGN, None, _parent_handler):
original_handlers[sig] = prev
try:
while not ctx.join() and not parent_stop.is_set():
pass
except BaseException:
logger.warning(
"Parent received unexpected exception, terminating children..."
)
for p in ctx.processes:
if p.is_alive():
p.terminate()
raise
finally:
for sig, handler in original_handlers.items():
signal.signal(sig, handler)
for p in ctx.processes:
p.join()
ctx.join()
def _is_external_launcher() -> bool:
"""Whether an external launcher (torchrun/elastic/manual env) started us."""
if dist.is_torchelastic_launched():
return True
if "LOCAL_WORLD_SIZE" in os.environ:
return True
if "RANK" in os.environ and "WORLD_SIZE" in os.environ:
return True
return False
def spawn_parallel_fn(
func: Callable,
world_size: int,
backend: str = "nccl",
master_addr: str = "localhost",
master_port: Optional[str] = None,
device_type: str = "cuda",
start_method: str = "spawn",
**kwargs,
):
if master_port is None:
master_port = find_free_port()
if _is_external_launcher():
strategy = TorchrunStrategy(
world_size, backend, master_addr, master_port, device_type, start_method
)
else:
strategy = LocalStrategy(
world_size, backend, master_addr, master_port, device_type, start_method
)
strategy.launch(func, **kwargs)