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paddlepaddle--paddle/python/paddle/distributed/passes/auto_parallel_gradient_merge.py
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2026-07-13 12:40:42 +08:00

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# Copyright (c) 2021 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.
from __future__ import annotations
import paddle
from paddle.distributed.auto_parallel.static.process_group import (
get_world_process_group,
)
from paddle.distributed.fleet.meta_optimizers.common import (
OpRole,
)
from paddle.framework import (
_current_expected_place_ as _get_device,
)
from .pass_base import PassBase, PassType, register_pass
world_process_group = get_world_process_group()
def _move_used_grad_op(used_grad_op, grad):
move_to_opt_block_flag = True
move_to_opt_ops = []
cannot_move_op = ["pd_op.send_v2", "pd_op.send"]
def find_move_op(backward_op):
nonlocal move_to_opt_block_flag
if not move_to_opt_block_flag or backward_op in move_to_opt_ops:
return
if backward_op.name() in cannot_move_op:
move_to_opt_block_flag = False
return
if backward_op.num_operands() == 1:
move_to_opt_block_flag = True
move_to_opt_ops.append(backward_op)
elif backward_op.name() == "pd_op.slice":
move_to_opt_ops.append(backward_op)
for i in range(0, backward_op.num_operands()):
if not grad.is_same(backward_op.operand_source(i)):
move_to_opt_ops.append(
backward_op.operand_source(i).get_defining_op()
)
move_to_opt_block_flag = True
else:
# NOTE(zhangwl):temp only consider one operand op
move_to_opt_block_flag = False
return
for op_result in backward_op.results():
for next_op in op_result.all_used_ops():
if next_op.op_role != int(OpRole.Optimize):
find_move_op(next_op)
find_move_op(used_grad_op)
if move_to_opt_block_flag:
for move_op in move_to_opt_ops:
move_op.op_role = int(OpRole.Optimize)
def _pir_append_gradient_merge_backward_op(
main_program,
startup_program,
params_grads,
):
main_block = main_program.global_block()
startup_block = startup_program.global_block()
# {param: gradient_merge_var} to insert scale op and fill_constant op
new_params_grads = []
place = _get_device()
if isinstance(place, paddle.framework.CUDAPlace):
place = paddle.framework.CUDAPlace(
paddle.distributed.ParallelEnv().dev_id
)
cur_place = paddle.base.libpaddle.Place()
cur_place.set_place(place)
for param, grad in params_grads:
if grad is None:
continue
assert not param.is_selected_row_type(), (
"SELECTED_ROWS is not supported in GradientMergeOptimizer for now"
)
grad_dtype = grad.dtype
grad_type = grad.type()
for op in grad.all_used_ops():
if op.has_attr("master_grad_cast"):
grad_dtype = op.result(0).dtype
grad_type = op.result(0).type()
# step1: create gradient_merge var and init with 0
# Add persistable gradient variables in startup_program
paddle.pir.set_insertion_point_to_block_end(startup_block)
gradient_merge_var = paddle.full(
shape=grad._local_shape, fill_value=0.0, dtype=grad_dtype
)
gradient_merge_var.persistable = True
paddle.pir.set_insertion_point_after(
gradient_merge_var.get_defining_op()
)
paddle._C_ops.set_persistable_value(
gradient_merge_var, param.name + "@GRAD@MERGE"
)
# step2: Accumulate persistable gradient variables in main_program
# NOTE(zhaoyingli): inplace operation must be 'a = a + b', cannot be 'a = b + a'
grad_defining_op = grad.get_defining_op()
paddle.pir.set_insertion_point_after(grad_defining_op)
new_gradient_merge_var = main_block.add_kwarg(
param.name + "@GRAD@MERGE", grad_type
)
new_gradient_merge_var.persistable = True
new_gradient_merge_var.place_attr = cur_place
new_gradient_merge_var_add = paddle._C_ops.add_(
new_gradient_merge_var, grad
)
new_gradient_merge_var_add_op = (
new_gradient_merge_var_add.get_defining_op()
)
new_gradient_merge_var_add_op.op_role = grad_defining_op.op_role
new_gradient_merge_var_add_op.dist_attr = (
paddle.base.libpaddle.pir.create_op_dist_attribute(
grad_defining_op.dist_attr.process_mesh,
grad_defining_op.dist_attr.operands(),
grad_defining_op.dist_attr.results(),
grad_defining_op.dist_attr.chunk_id,
)
)
new_gradient_merge_var_add_op.set_bool_attr("grad_merge_add", True)
# NOTE(zhangweilong): grad may in different device in auto_parallel, so need consider all_gather/all_reduce/split/... op
for used_grad_op in grad.all_used_ops():
_move_used_grad_op(used_grad_op, grad)
opt_ops_use_grad = [
op
for op in grad.all_used_ops()
if op.op_role == int(OpRole.Optimize)
]
grad.replace_grad_users_with(
new_gradient_merge_var, set(opt_ops_use_grad)
)
# reset gradient merge var to zero after finishing optimization
paddle.pir.set_insertion_point_to_block_end(main_block)
set_value = paddle.full(
shape=[1], fill_value=float(0), dtype=grad_dtype
)
new_gradient_merge_var_zero = paddle._C_ops.set_value_with_tensor_(
new_gradient_merge_var, set_value, [], [], [], [], [], []
)
set_value_op = new_gradient_merge_var_zero.get_defining_op()
set_value_op.op_role = int(OpRole.Optimize)
for id in range(1, set_value_op.num_operands()):
op_input = set_value_op.operand_source(id)
op_input.get_defining_op().op_role = int(OpRole.Optimize)
# step3: Construct new_params_grads and grad_to_gradient_merge
new_params_grads.append((param, new_gradient_merge_var))
return new_params_grads
def _pir_move_reduce_to_backward_stage(main_program):
pass
def _pir_remove_cast_for_master_grad(main_program, params_grads):
for op in main_program.global_block().ops:
if op.has_attr("master_grad_cast"):
op.result(0).replace_all_uses_with(op.operand_source(0))
op.erase()
def _find_trivial_optimizer_ops(block):
optimizer_ops = []
for op in block.ops:
if "adam" in op.name() or "sgd" in op.name():
optimizer_ops.append(op)
return optimizer_ops
def _get_prev_op(block, optimizer_op):
found = False
for op in reversed(block.ops):
if found:
return op
if op.id == optimizer_op.id:
found = True
return None
def _insert_scale_op_after(target_value, optimizer_op, scale, bias=0.0):
scaled_grad = paddle._C_ops.scale_(target_value, scale, bias, False)
scale_op = scaled_grad.get_defining_op()
scale_op.op_role = int(OpRole.Optimize)
full_op = scale_op.operand_source(1).get_defining_op()
assert full_op.name() == "pd_op.full", (
f"The defining op of the scale value should be `pd_op.full`, but got {full_op.name()}"
)
full_op.op_role = int(OpRole.Optimize)
if "adam" in optimizer_op.name():
optimizer_op.operand(1).set_source(scaled_grad)
elif "sgd" in optimizer_op.name():
optimizer_op.operand(2).set_source(scaled_grad)
def _append_scale_op_before_comm(block, new_params_to_grads, k_steps):
for op in reversed(block.ops):
if op.op_role == int(OpRole.Backward):
paddle.pir.set_insertion_point_after(op)
break
for _, new_grad in new_params_to_grads:
new_grad = paddle._C_ops.scale_(new_grad, 1.0 / k_steps, 0.0, False)
scale_op = new_grad.get_defining_op()
scale_op.op_role = int(OpRole.Optimize)
full_op = scale_op.operand_source(1).get_defining_op()
assert full_op.name() == "pd_op.full", (
f"The defining op of the scale value should be `pd_op.full`, but got {full_op.name()}"
)
full_op.op_role = int(OpRole.Optimize)
paddle.pir.set_insertion_point_to_block_end(block)
def _append_scale_op_after_comm(block, optimizer_ops, k_steps):
for optimizer_op in optimizer_ops:
target_value = None
if "adam" in optimizer_op.name(): # adam and adamw are included
target_value = optimizer_op.operand_source(1)
elif "sgd" in optimizer_op.name():
target_value = optimizer_op.operand_source(2)
else:
raise NotImplementedError(
f"We yet support adamw, adam and sgd, but got {optimizer_op.name()}"
)
assert target_value is not None, (
"target_value is not expected to be None"
)
insertion_point = target_value.get_defining_op()
if insertion_point is None:
# target_value is a gradient_merge_var, which hasn't defining_op
# so we find the prev op of optimizer_op, inserting a scale op behind.
insertion_point = _get_prev_op(block, optimizer_op)
paddle.pir.set_insertion_point_after(insertion_point)
_insert_scale_op_after(target_value, optimizer_op, 1.0 / k_steps)
paddle.pir.set_insertion_point_to_block_end(block)
def _pir_append_scale_op(program, new_params_to_grads, k_steps):
block = program.global_block()
optimizer_ops = _find_trivial_optimizer_ops(block)
if len(optimizer_ops) > 0:
_append_scale_op_after_comm(block, optimizer_ops, k_steps)
else:
_append_scale_op_before_comm(block, new_params_to_grads, k_steps)
def _pir_parse_program(
main_program,
startup_program,
params_grads,
k_steps,
avg,
gradient_sync_after_accumulate,
):
# step1: append gradient merge backward op to main_program
new_params_to_grads = _pir_append_gradient_merge_backward_op(
main_program, startup_program, params_grads
)
# step2: move back reduce op to backward stage
if not gradient_sync_after_accumulate:
_pir_move_reduce_to_backward_stage(main_program, params_grads)
# _pir_remove_cast_for_master_grad(main_program, params_grads)
# step3: append scale op
if avg:
_pir_append_scale_op(main_program, new_params_to_grads, k_steps)
@register_pass("auto_parallel_gradient_merge_pass")
class GradientMergePass(PassBase):
def __init__(self):
super().__init__()
self.set_attr("k_steps", -1)
self.set_attr("avg", True)
self._in_pir_mode = paddle.base.framework.get_flags(
"FLAGS_enable_pir_api"
)["FLAGS_enable_pir_api"]
def _check_self(self):
if self.get_attr("k_steps") < 1:
return False
return True
def _check_conflict(self, other_pass):
return True
def _type(self):
return PassType.COMM_OPT
def _apply_single_impl(self, main_program, startup_program, context):
k_steps = self.get_attr("k_steps", -1)
avg = self.get_attr("avg", False)
params_grads = self.get_attr("params_grads")
gradient_sync_after_accumulate = self.get_attr(
"gradient_sync_after_accumulate", False
)
if self._in_pir_mode:
with paddle.static.program_guard(main_program, startup_program):
_pir_parse_program(
main_program,
startup_program,
params_grads,
k_steps,
avg,
gradient_sync_after_accumulate,
)
else:
raise NotImplementedError(
"auto_parallel_gradient_merge_pass() only support PIR now."
)