pytorch/torch/distributed/rpc/backend_registry.py
Aaron Gokaslan 292af3cc89 [BE][Ez]: ISC001 Auto concatenate implicit one line strings (#146408)
Apply ruff rule about implicit string concatenation, this autofixes strings that are all the same type and on the same line. These lines are broken up likely as the result of autoformatters in the past. All fixes are automated using the autofixes in ISC001.

Pull Request resolved: https://github.com/pytorch/pytorch/pull/146408
Approved by: https://github.com/justinchuby, https://github.com/janeyx99
2025-02-04 19:07:04 +00:00

431 lines
16 KiB
Python

# mypy: allow-untyped-defs
import collections
import enum
from typing import cast
import torch
import torch.distributed as dist
from . import api, constants as rpc_constants
from ._utils import _group_membership_management, _update_group_membership
__all__ = [
"backend_registered",
"register_backend",
"construct_rpc_backend_options",
"init_backend",
"BackendValue",
"BackendType",
]
BackendValue = collections.namedtuple(
"BackendValue", ["construct_rpc_backend_options_handler", "init_backend_handler"]
)
def _backend_type_repr(self):
return "BackendType." + self.name
_backend_type_doc = """
An enum class of available backends.
PyTorch ships with a builtin ``BackendType.TENSORPIPE`` backend.
Additional ones can be registered using the
:func:`~torch.distributed.rpc.backend_registry.register_backend` function.
"""
# Create an enum type, `BackendType`, with empty members.
# Can't handle Function Enum API (mypy bug #9079)
BackendType = enum.Enum(value="BackendType", names={}) # type: ignore[misc]
# Unable to assign a function a method (mypy bug #2427)
BackendType.__repr__ = _backend_type_repr # type: ignore[assignment]
if BackendType.__doc__:
BackendType.__doc__ = _backend_type_doc
def backend_registered(backend_name):
"""
Checks if backend_name is registered as an RPC backend.
Args:
backend_name (str): string to identify the RPC backend.
Returns:
True if the backend has been registered with ``register_backend``, else
False.
"""
return backend_name in BackendType.__members__.keys()
def register_backend(
backend_name, construct_rpc_backend_options_handler, init_backend_handler
):
"""Registers a new RPC backend.
Args:
backend_name (str): backend string to identify the handler.
construct_rpc_backend_options_handler (function):
Handler that is invoked when
rpc_backend.construct_rpc_backend_options(**dict) is called.
init_backend_handler (function): Handler that is invoked when the
`_init_rpc_backend()` function is called with a backend.
This returns the agent.
"""
global BackendType
if backend_registered(backend_name):
raise RuntimeError(f"RPC backend {backend_name}: already registered")
# Create a new enum type, `BackendType`, with extended members.
existing_enum_dict = {member.name: member.value for member in BackendType}
extended_enum_dict = dict(
{
backend_name: BackendValue(
construct_rpc_backend_options_handler=construct_rpc_backend_options_handler,
init_backend_handler=init_backend_handler,
)
},
**existing_enum_dict,
)
# Can't handle Function Enum API (mypy bug #9079)
BackendType = enum.Enum(value="BackendType", names=extended_enum_dict) # type: ignore[misc]
# Unable to assign a function a method (mypy bug #2427)
BackendType.__repr__ = _backend_type_repr # type: ignore[assignment]
if BackendType.__doc__:
BackendType.__doc__ = _backend_type_doc
return BackendType[backend_name]
def construct_rpc_backend_options(
backend,
rpc_timeout=rpc_constants.DEFAULT_RPC_TIMEOUT_SEC,
init_method=rpc_constants.DEFAULT_INIT_METHOD,
**kwargs,
):
return backend.value.construct_rpc_backend_options_handler(
rpc_timeout, init_method, **kwargs
)
def init_backend(backend, *args, **kwargs):
return backend.value.init_backend_handler(*args, **kwargs)
def _init_process_group(store, rank, world_size):
# Initialize ProcessGroup.
process_group_timeout = rpc_constants.DEFAULT_PROCESS_GROUP_TIMEOUT
# We're using a bunch of private APIs here since `new_group` requires the
# default group to be initialized.
group = dist.ProcessGroupGloo(store, rank, world_size, process_group_timeout)
assert group is not None, "Failed to initialize default ProcessGroup."
if (rank != -1) and (rank != group.rank()):
raise RuntimeError(f"rank argument {rank} doesn't match pg rank {group.rank()}")
if (world_size != -1) and (world_size != group.size()):
raise RuntimeError(
f"world_size argument {world_size} doesn't match pg size {group.size()}"
)
return group
def _tensorpipe_construct_rpc_backend_options_handler(
rpc_timeout,
init_method,
num_worker_threads=rpc_constants.DEFAULT_NUM_WORKER_THREADS,
_transports=None,
_channels=None,
**kwargs,
):
from . import TensorPipeRpcBackendOptions
return TensorPipeRpcBackendOptions(
rpc_timeout=rpc_timeout,
init_method=init_method,
num_worker_threads=num_worker_threads,
_transports=_transports,
_channels=_channels,
)
def _tensorpipe_validate_devices(devices, device_count):
return all(
d.type == "cpu" or (d.type == "cuda" and 0 <= d.index < device_count)
for d in devices
)
# detect if any worker has invalid device_map configurations, and return
# reverse device maps
def _tensorpipe_exchange_and_check_all_device_maps(
my_name, my_device_count, my_device_maps, my_devices, group
):
gathered: list[
tuple[str, int, dict[str, dict[torch.device, torch.device]], list[torch.device]]
] = [("", 0, {}, []) for _ in range(group.size())]
dist.all_gather_object(
gathered, (my_name, my_device_count, my_device_maps, my_devices), group
)
all_names = [name for name, _, _, _ in gathered]
all_device_counts = {name: count for name, count, _, _ in gathered}
all_device_maps = {name: map_ for name, _, map_, _ in gathered}
all_devices = {name: devices for name, _, _, devices in gathered}
_validate_device_maps(all_names, all_device_counts, all_device_maps, all_devices)
# passed all checked, construct reverse mapping and get list of devices handled by this agent
reverse_device_maps = _create_reverse_mapping(my_name, all_names, all_device_maps)
my_devices = _create_device_list(my_devices, my_device_maps, reverse_device_maps)
return reverse_device_maps, my_devices
def _validate_device_maps(
all_names, all_device_counts, all_device_maps, all_devices, is_static_group=True
):
for node in all_names:
devices = all_devices[node]
if len(set(devices)) != len(devices):
raise ValueError(f"Node {node} has duplicated devices\ndevices = {devices}")
if not _tensorpipe_validate_devices(devices, all_device_counts[node]):
raise ValueError(
f"Node {node} has devices with invalid indices\n"
f"devices = {devices}\n"
f"device count = {all_device_counts[node]}"
)
for source_node in all_names:
# For dynamic group (non-static) do not check the target node name since it may not have joined yet
if is_static_group and not set(all_device_maps[source_node].keys()).issubset(
all_names
):
raise ValueError(
f"Node {source_node} has invalid target node names in its device maps\n"
f"device maps = {all_device_maps[source_node].keys()}\n"
f"node names = {all_names}"
)
for target_node, map_ in all_device_maps[source_node].items():
if len(set(map_.values())) != len(map_):
raise ValueError(
f"Node {source_node} has duplicated target devices "
f"in its device map for {target_node}\n"
f"device map = {map_}"
)
if all_devices[source_node]:
if not set(map_.keys()).issubset(all_devices[source_node]):
raise ValueError(
f"Node {source_node} has unexpected source devices "
f"in its device map for {target_node}\n"
f"device map = {map_}\n"
f"devices = {all_devices[source_node]}"
)
elif not _tensorpipe_validate_devices(
map_.keys(), all_device_counts[source_node]
):
raise ValueError(
f"Node {source_node} has source devices with invalid indices "
f"in its device map for {target_node}\n"
f"device map = {map_}\n"
f"device count = {all_device_counts[source_node]}"
)
if all_devices.get(target_node, []):
if not set(map_.values()).issubset(all_devices[target_node]):
raise ValueError(
f"Node {source_node} has unexpected target devices "
f"in its device map for {target_node}\n"
f"device map = {map_}\n"
f"devices = {all_devices[target_node]}"
)
elif target_node in all_device_counts and not _tensorpipe_validate_devices(
map_.values(), all_device_counts[target_node]
):
raise ValueError(
f"Node {source_node} has target devices with invalid indices "
f"in its device map for {target_node}\n"
f"device map = {map_}\n"
f"device count = {all_device_counts[target_node]}"
)
def _create_device_list(my_devices, my_device_maps, reverse_device_maps):
if not my_devices:
devices_set: set[torch.device] = set()
for map_ in my_device_maps.values():
devices_set.update(map_.keys())
for map_ in reverse_device_maps.values():
devices_set.update(map_.keys())
devices_set.discard(torch.device("cpu"))
my_devices = list(devices_set)
my_devices = sorted(my_devices, key=lambda d: d.index)
return my_devices
def _create_reverse_mapping(my_name, all_names, all_device_maps):
reverse_device_maps: dict[str, dict[torch.device, torch.device]] = {}
for node in all_names:
if my_name in all_device_maps[node]:
reverse_device_maps[node] = {
v: k for k, v in all_device_maps[node][my_name].items()
}
return reverse_device_maps
def _get_device_infos():
from . import TensorPipeAgent
agent = cast(TensorPipeAgent, api._get_current_rpc_agent())
opts = agent._get_backend_options()
device_count = torch.cuda.device_count()
if torch.cuda.is_available() and opts.devices:
torch.cuda.init()
return device_count, opts.device_maps, opts.devices
def _set_devices_and_reverse_device_map(agent):
from . import TensorPipeAgent
agent = cast(TensorPipeAgent, agent)
# Group state is retrieved from local agent
# On initialization, tensorpipe agent retrieves information from all existing workers, so group state is valid
my_worker_info = agent.get_worker_info()
my_name = my_worker_info.name
all_worker_infos = agent.get_worker_infos()
# One round to get device_maps of all workers and construct reverse device maps
all_device_counts, all_device_maps, all_devices, all_names = {}, {}, {}, []
for worker_info in all_worker_infos:
worker_name = worker_info.name
if worker_name != my_name:
# TODO: make async?
device_count, device_map, devices = api.rpc_sync(
worker_name, _get_device_infos
)
else:
opts = agent._get_backend_options()
device_count, device_map, devices = (
torch.cuda.device_count(),
opts.device_maps,
opts.devices,
)
all_device_counts[worker_name] = device_count
all_device_maps[worker_name] = device_map
all_devices[worker_name] = devices
all_names.append(worker_name)
_validate_device_maps(
all_names,
all_device_counts,
all_device_maps,
all_devices,
is_static_group=False,
)
reverse_device_maps = _create_reverse_mapping(my_name, all_names, all_device_maps)
# Perform RPC call to all workers, including itself, to include newly joined worker information and device maps
for worker_name in all_names:
# Set device list for each worker
all_devices[worker_name] = _create_device_list(
all_devices[worker_name], all_device_maps[worker_name], reverse_device_maps
)
api.rpc_sync(
worker_name,
_update_group_membership,
args=(my_worker_info, all_devices[worker_name], reverse_device_maps, True),
)
def _tensorpipe_init_backend_handler(
store, name, rank, world_size, rpc_backend_options
):
from . import TensorPipeAgent, TensorPipeRpcBackendOptions
if not isinstance(store, dist.Store):
raise TypeError(f"`store` must be a c10d::Store. {store}")
if not isinstance(rpc_backend_options, TensorPipeRpcBackendOptions):
raise TypeError(
f"`rpc_backend_options` must be a `TensorPipeRpcBackendOptions`. {rpc_backend_options}"
)
device_count = torch.cuda.device_count()
is_static_group = True if world_size else False
# world_size is specified so this is a static group (ranks cannot join and leave)
if is_static_group:
# The agent's join method is required to behave like a barrier and perform
# collective operations, for which it relies on a process group, instead of
# re-implementing this on top of RPCs.
group = _init_process_group(store, rank, world_size)
reverse_device_maps, devices = _tensorpipe_exchange_and_check_all_device_maps(
name,
device_count,
rpc_backend_options.device_maps,
rpc_backend_options.devices,
group,
)
if torch.cuda.is_available() and devices:
# It's necessary to initialize PyTorch CUDA states here (e.g.,
# CUDACachingAllocator). If this is missing, we could hit errors like
# "allocator not initialized", because other processes might send
# CUDA-related RPC request to this process before user code in this
# process initializes its PyTorch CUDA states.
torch.cuda.init()
# TODO: add try-except and destroy _agent in all processes if any fails.
agent = TensorPipeAgent(
store,
name,
rank,
world_size,
rpc_backend_options,
reverse_device_maps,
devices,
)
api._init_rpc_states(agent)
# Run one dummy round of RPC to initialize channels/transports. Without
# this, it's easy to hit timeout in rpc.shutdown() if there is no other RPC
# on that process before rpc.shutdown(), as the agent initialization can
# take longer than 5s.
api._all_gather(None, timeout=rpc_backend_options.rpc_timeout)
# Need a barrier here to make sure no peers leave before the rank0 finishes
# _all_gather
group.barrier().wait()
return agent
# initialization for dynamic rpc (ranks can join and leave)
else:
with _group_membership_management(store, name, True):
# Construct TPAgent with empty reverse_device_map and devices
# these properties will be updated after initialization
agent = TensorPipeAgent(
store,
name,
rank,
world_size,
rpc_backend_options,
{},
[],
)
api._init_rpc_states(agent)
try:
# Notify all workers in group this rank has joined and set devices and reverse_device_map
# This is a synchronous operation that completes once all existing ranks are updated
_set_devices_and_reverse_device_map(agent)
except Exception:
api.shutdown()
raise
return agent
register_backend(
"TENSORPIPE",
_tensorpipe_construct_rpc_backend_options_handler,
_tensorpipe_init_backend_handler,
)