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paddlepaddle--paddle/python/paddle/distributed/fleet/base/strategy_group.py
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2026-07-13 12:40:42 +08:00

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Python

# Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
#
# 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 paddle.distributed as dist
from paddle.distributed.fleet.layers.mpu import RNGStatesTracker
class StrategyGroupBase:
"""
The base class of communication group with distributed strategy.
Args:
list_of_ranks: A 2D-array, such as `[[0, 1, 2, 3], [4, 5, 6, 7]]`. Ranks in sublist represents
they are in the same communication group.
Returns:
The instance of strategy group.
Examples:
.. code-block:: pycon
>>> # doctest: +REQUIRES(env: DISTRIBUTED)
>>> import paddle.distributed as dist
>>> from paddle.distributed.fleet.base.strategy_group import StrategyGroupBase
>>> dist.init_parallel_env()
>>> strategy_group = dist.fleet.base.strategy_group.StrategyGroupBase([[0, 1], [2, 3]])
>>> print(strategy_group.world_size)
2
"""
def __init__(self, list_of_ranks):
"""
Initialize the communication group.
"""
assert dist.is_initialized(), (
"The global communication group need to be initialized."
)
assert len(list_of_ranks), "The list_of_ranks can not be empty."
self._rank = dist.get_rank()
self._list_of_ranks = list_of_ranks
self._group = self._create_group()
self.random_states_tracker = RNGStatesTracker()
def add_random_seed(self, name, seed):
"""
Add random seed for current rank.
"""
self.random_states_tracker.add(name, seed)
def get_random_states_tracker(self):
"""
Get the random states tracker.
"""
return self.random_states_tracker
@property
def world_size(self):
"""
The world size of communication group.
Returns:
Integer if the world_size of each group are equal, or a list of world_size if they are not equal.
"""
world_size_list = []
for ranks in self._list_of_ranks:
world_size_list.append(len(ranks))
is_value = all(
world_size == world_size_list[0] for world_size in world_size_list
)
return world_size_list[0] if is_value else world_size_list
@property
def group(self):
"""
The communication group which current rank belongs to.
Returns:
Group if current rank only belong to single communication group, or a list of Group if it belongs many.
"""
return self._group
def _create_group(self):
self.list_of_group = []
for ranks in self._list_of_ranks:
group = dist.new_group(ranks=ranks)
if self._rank in ranks:
self.list_of_group.append(group)
if not self.list_of_group:
return None
else:
return (
self.list_of_group[0]
if len(self.list_of_group) == 1
else self.list_of_group
)
def __repr__(self):
debug_str = f"seed: {self._seed}; "
if not self.list_of_group:
return debug_str + "No group."
for i in range(len(self.list_of_group)):
debug_str += f"Group[{i}]: {self.list_of_group[i]}; "
return debug_str
class DPGroup(StrategyGroupBase):
"""
The communication group strategy for data parallel.
Args:
list_of_ranks: A 2D-array, such as `[[0, 1, 2, 3], [4, 5, 6, 7]]`. Ranks in sublist represents
they are in the same communication group.
Returns:
The instance of data parallel strategy group.
"""
def __init__(self, list_of_ranks):
super().__init__(list_of_ranks)
assert not isinstance(self.group, list), (
f"Rank {self._rank} belongs to multi dp groups"
)
class MPGroup(StrategyGroupBase):
"""
The communication group strategy for model parallel.
Args:
list_of_ranks: A 2D-array, such as `[[0, 1, 2, 3], [4, 5, 6, 7]]`. Ranks in sublist represents
they are in the same communication group.
Returns:
The instance of model parallel strategy group.
"""
def __init__(self, list_of_ranks):
super().__init__(list_of_ranks)
assert not isinstance(self.group, list), (
f"Rank {self._rank} belongs to multi mp groups"
)
class ShardingGroup(StrategyGroupBase):
"""
The communication group strategy for sharding parallel.
Args:
list_of_ranks: A 2D-array, such as `[[0, 1, 2, 3], [4, 5, 6, 7]]`. Ranks in sublist represents
they are in the same communication group.
Returns:
The instance of sharding parallel strategy group.
"""
def __init__(self, list_of_ranks):
super().__init__(list_of_ranks)
assert not isinstance(self.group, list), (
f"Rank {self._rank} belongs to multi sharding groups"
)
class PPGroup(StrategyGroupBase):
"""
The communication group strategy for pipeline parallel.
Args:
list_of_ranks: A 2D-array, such as `[[0, 1, 2, 3], [4, 5, 6, 7]]`. Ranks in sublist represents
they are in the same communication group.
Returns:
The instance of pipeline parallel strategy group.
"""
def __init__(self, list_of_ranks):
super().__init__(list_of_ranks)
assert not isinstance(self.group, list), (
f"Rank {self._rank} belongs to multi pp groups"
)
self._send_next_group = None
self._send_prev_group = None
self._recv_next_group = None
self._recv_prev_group = None
self._rank_of_next_stage = None
self._rank_of_prev_stage = None
if self.world_size > 1:
self._create_p2p_group()
@property
def rank_of_prev_stage(self):
"""
Rank of the previous pp stage.
Returns:
The global rank of previous pp stage. `None` if without previous.
"""
return self._rank_of_prev_stage
@property
def rank_of_next_stage(self):
"""
Rank of the next pp stage.
Returns:
The global rank of next pp stage. `None` if without next.
"""
return self._rank_of_next_stage
@property
def p2p_groups(self):
"""
Communication subgroup in order to switch data with previous and next stage.
Returns:
Four subgroups including send/recv to/from prev/next.
"""
return (
self._send_next_group,
self._send_prev_group,
self._recv_next_group,
self._recv_prev_group,
)
def _create_p2p_group(self):
degree = self.world_size
for ranks in self._list_of_ranks:
for idx, rank in enumerate(ranks):
next_rank = ranks[(idx + 1) % degree]
prev_rank = ranks[(idx - 1) % degree]
if self._rank == rank:
self._rank_of_next_stage = next_rank
self._rank_of_prev_stage = prev_rank
next_group = dist.new_group(ranks=[rank, next_rank])
if self._rank == rank:
self._send_next_group = next_group
elif self._rank == next_rank:
self._recv_prev_group = next_group
prev_group = dist.new_group(ranks=[prev_rank, rank])
if self._rank == rank:
self._send_prev_group = prev_group
elif self._rank == prev_rank:
self._recv_next_group = prev_group
assert (
self._send_next_group
and self._send_prev_group
and self._recv_next_group
and self._recv_prev_group
), f"Error occurs while creating p2p group for rank {self._rank}."