# 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 import paddle.fluid as fluid from paddle.fluid import core, unique_name from .meta_optimizer_base import MetaOptimizerBase from .common import OpRole, OP_ROLE_KEY, OP_ROLE_VAR_KEY, CollectiveHelper, is_loss_grad_op, is_backward_op, is_optimizer_op class RawProgramOptimizer(MetaOptimizerBase): def __init__(self, optimizer): super(RawProgramOptimizer, self).__init__(optimizer) self.inner_opt = optimizer self.meta_optimizers_white_list = [ "RecomputeOptimizer", "AMPOptimizer", "GradientMergeOptimizer", "LambOptimizer", "LarsOptimizer", "DGCOptimizer", "LocalSGDOptimizer", ] self.meta_optimizers_black_list = [ "GraphExecutionOptimizer", ] self.global_ring_id = 0 def _set_basic_info(self, loss, role_maker, user_defined_optimizer, user_defined_strategy): super(RawProgramOptimizer, self)._set_basic_info(loss, role_maker, user_defined_optimizer, user_defined_strategy) self.without_graph_optimization = user_defined_strategy.without_graph_optimization self.fuse_all_reduce_ops = user_defined_strategy.fuse_all_reduce_ops if self.fuse_all_reduce_ops: self.fuse_grad_size_in_num = user_defined_strategy.fuse_grad_size_in_num self.calc_comm_same_stream = user_defined_strategy._calc_comm_same_stream def _can_apply(self): if not self.role_maker._is_collective: return False if self.without_graph_optimization == True: return True return False def _disable_strategy(self, dist_strategy): dist_strategy.without_graph_optimization = False def _enable_strategy(self, dist_strategy, context): dist_strategy.without_graph_optimization = True def _broadcast_params(self, ring_id): block = self.startup_program.global_block() param = None for param in block.iter_parameters(): if param.is_distributed: continue block.append_op(type='c_broadcast', inputs={'X': param}, outputs={'Out': param}, attrs={ 'ring_id': ring_id, 'root': 0, OP_ROLE_KEY: OpRole.Forward }) if not param: return # no parameter on this device block.append_op(type='c_sync_comm_stream', inputs={'X': param}, outputs={'Out': param}, attrs={ 'ring_id': ring_id, OP_ROLE_KEY: OpRole.Forward }) def _get_process_group_info(self): # global ring info self.global_endpoints = self.endpoints self.global_rank = self.rank self.global_nranks = self.nranks def _init_process_group(self): self._get_process_group_info() collective_helper = CollectiveHelper(self.role_maker, wait_port=False) # Create global ring for all gpus (ring_id = 0) collective_helper._init_communicator(self.startup_program, self.current_endpoint, self.global_endpoints, self.global_rank, self.global_ring_id, True, self.global_ring_id, True) self._broadcast_params(self.global_ring_id) def minimize_impl(self, loss, startup_program=None, parameter_list=None, no_grad_set=None): self.endpoints = self.role_maker._get_trainer_endpoints() self.current_endpoint = self.endpoints[self.role_maker._worker_index()] self.rank = self.role_maker._worker_index() self.nranks = self.role_maker._worker_num() if startup_program is None: startup_program = fluid.default_startup_program() self.startup_program = startup_program block = loss.block program = block.program self.main_program = program optimize_ops, params_grads = self.inner_opt.minimize( loss, startup_program, parameter_list, no_grad_set) if self.nranks == 1: return optimize_ops, params_grads self._init_process_group() self.main_program = program if self.nranks > 1: self._transpile_main_program(loss) return optimize_ops, params_grads def _find_gradient_merge_block(self): GRAD_MERGE_COND_NAME = "grad_merge_cond_name" gm_cond_var_name = None for op in self.main_program.global_block().ops: if GRAD_MERGE_COND_NAME not in op.attr_names: continue if gm_cond_var_name is None: gm_cond_var_name = op.attr(GRAD_MERGE_COND_NAME) else: assert gm_cond_var_name == op.attr( GRAD_MERGE_COND_NAME ), "multiple gradient merge condition found" if gm_cond_var_name is None: return None cond_op = None # false_fn of gm is None, so we should only find one block for op in self.main_program.global_block().ops: if op.type != 'conditional_block' or 'Cond' not in op.input_names: continue cond_vars = op.input('Cond') if not cond_vars or cond_vars[0] != gm_cond_var_name: continue assert cond_op is None, "multiple gradient merge block found" cond_op = op assert cond_op is not None, "cannot find gradient merge block" return cond_op._block_attr("sub_block") def _insert_allreduce_ops_for_gm(self, gm_block): block = self.main_program.global_block() first_optimize_op_idx = None for i, op in reversed(list(enumerate(gm_block.ops))): if is_backward_op(op) and first_optimize_op_idx is None: first_optimize_op_idx = i + 1 break if first_optimize_op_idx is None: first_optimize_op_idx = 0 param_vars = [] grad_vars = [] for op in block.ops: if is_backward_op(op) and \ OP_ROLE_VAR_KEY in op.attr_names: op_role_var = op.attr(OP_ROLE_VAR_KEY) assert len(op_role_var) % 2 == 0 for i in range(0, len(op_role_var), 2): param = block.var(op_role_var[i]) grad = block.var(op_role_var[i + 1]) if param.is_distributed: continue param_vars.append(param) grad_vars.append(grad) if not grad_vars: return gm_block._insert_op(first_optimize_op_idx, type="c_sync_calc_stream", inputs={'X': grad_vars[0]}, outputs={'Out': grad_vars[0]}, attrs={OP_ROLE_KEY: OpRole.Backward}) insert_op_num = 1 ring_id = self.global_ring_id # NOTE: can perform fuse allreduce inside the loop in the future for i, (p, g) in enumerate(zip(param_vars, grad_vars)): gm_block._insert_op(first_optimize_op_idx + insert_op_num, type="c_allreduce_sum", inputs={'X': g}, outputs={'Out': g}, attrs={ 'ring_id': ring_id, OP_ROLE_KEY: OpRole.Backward, }) insert_op_num += 1 gm_block._insert_op(first_optimize_op_idx + insert_op_num, type="c_sync_comm_stream", inputs={'X': grad_vars}, outputs={'Out': grad_vars}, attrs={ 'ring_id': ring_id, OP_ROLE_KEY: OpRole.Backward, }) def _transpile_main_program(self, loss): self._insert_loss_grad_ops(loss) gm_block = self._find_gradient_merge_block() if gm_block is not None: # TODO(zjl): support fuse allreduce self._insert_allreduce_ops_for_gm(gm_block) return if self.fuse_all_reduce_ops and self.fuse_grad_size_in_num > 1: self._allreduce_fusion_program() else: self._insert_allreduce_ops() def _insert_loss_grad_ops(self, loss): """ In order to keep the learning rate consistent in different numbers of training workers, we scale the loss grad by the number of workers """ block = self.main_program.global_block() for idx, op in reversed(list(enumerate(block.ops))): if is_loss_grad_op(op): loss_grad_var = block.vars[op.output_arg_names[0]] block._insert_op(idx + 1, type='scale', inputs={'X': loss_grad_var}, outputs={'Out': loss_grad_var}, attrs={ 'scale': 1.0 / self.nranks, OP_ROLE_KEY: OpRole.Backward }) def _insert_allreduce_ops(self): block = self.main_program.global_block() ring_id = self.global_ring_id grad = None grad_vars = [] for idx, op in reversed(list(enumerate(block.ops))): if is_backward_op(op) and \ OP_ROLE_VAR_KEY in op.attr_names: op_role_var = op.attr(OP_ROLE_VAR_KEY) if len(op_role_var) == 0: continue assert len(op_role_var) % 2 == 0 offset = 1 for i in range(0, len(op_role_var), 2): param_name = op_role_var[i] param = block.var(param_name) grad_name = op_role_var[i + 1] grad = block.var(grad_name) if param.is_distributed: continue grad_vars.append(grad) block._insert_op(idx + offset, type='c_sync_calc_stream', inputs={'X': grad}, outputs={'Out': grad}, attrs={ OP_ROLE_KEY: OpRole.Backward, }) offset += 1 block._insert_op(idx + offset, type='c_allreduce_sum', inputs={'X': grad}, outputs={'Out': grad}, attrs={ 'ring_id': ring_id, OP_ROLE_KEY: OpRole.Backward }) if grad is None: return for idx, op in enumerate(block.ops): if is_optimizer_op(op): block._insert_op(idx, type='c_sync_comm_stream', inputs={'X': grad_vars}, outputs={'Out': grad_vars}, attrs={ 'ring_id': ring_id, OP_ROLE_KEY: OpRole.Backward }) break # This function helps reduce the number of allreduce by integrating op, which can save communication time. # to use allreduce fuse, follow these codes: # strategy = paddle.distributed.fleet.DistributedStrategy() # strategy.without_graph_optimization = True # strategy.fuse_all_reduce_ops = True # strategy.calc_comm_same_stream = False # strategy.fuse_grad_size_in_num = 8 def _allreduce_fusion_program(self): block = self.main_program.global_block() ring_id = self.global_ring_id param_grads = [] first_backward_idx = -1 # find all grad params for idx, op in enumerate(block.ops): if first_backward_idx == -1 and \ is_backward_op(op): first_backward_idx = idx if is_backward_op(op) and \ OP_ROLE_VAR_KEY in op.attr_names: op_role_var = op.attr(OP_ROLE_VAR_KEY) if len(op_role_var) == 0: continue assert len(op_role_var) % 2 == 0, "vars need to be one param var followed by one grad var, " \ "but got odd number of vars" for i in range(0, len(op_role_var), 2): param_name = op_role_var[i] param = block.var(param_name) grad_name = op_role_var[i + 1] grad = block.var(grad_name) if param.is_distributed: continue param_grads.append((param, grad)) outputs_name_to_idx = self.__get_ouputs_name_to_idx( first_backward_idx, block) # structure of grad_param_segments is # [([grad0, grad1], [param0, param1]), ([grad2, grad3], [param2, param3])] # each entry of the list is a tuple stores the grads segment list and # the corresponding params segment list grad_param_segments = [] last_dtype = None # split the grad based on dtype and fused size for param, grad in param_grads: if len(grad_param_segments) == 0 \ or len(grad_param_segments[-1][0]) == self.fuse_grad_size_in_num \ or grad.dtype != last_dtype: grad_param_segments.append(([grad], [param])) last_dtype = grad.dtype else: grad_param_segments[-1][0].append(grad) grad_param_segments[-1][1].append(param) if len(grad_param_segments) == 0: return fused_vars = [None] * len(grad_param_segments) for i in range(len(grad_param_segments) - 1, -1, -1): # travers the grad_param_segments in backward # not to use reversed since needs the absolute index value grad_segment, param_segment = grad_param_segments[i] # insert coalesce tensor fused_var = block.create_var(name=unique_name.generate( 'FusedOutput_{}'.format(grad_segment[0].name)), dtype=grad_segment[0].dtype, persistable=False, stop_gradient=True) fused_vars[i] = fused_var after_idx = outputs_name_to_idx[grad_segment[-1]][1] block._insert_op_without_sync(after_idx + 1, type='c_allreduce_sum', inputs={'X': fused_var}, outputs={'Out': fused_var}, attrs={ 'ring_id': ring_id, 'use_calc_stream': self.calc_comm_same_stream, OP_ROLE_KEY: OpRole.Backward }) if not self.calc_comm_same_stream: block._insert_op_without_sync( after_idx + 1, type='c_sync_calc_stream', inputs={'X': fused_var}, outputs={'Out': fused_var}, attrs={OP_ROLE_KEY: OpRole.Backward}) # update the outputs_name_to_idx after insertion of sync/allreduce ops outputs_name_to_idx = self.__get_ouputs_name_to_idx( first_backward_idx, block) # the before_idx is not guaranteed sorted, therefore we have to find the # topology to insert the coalesce ops pos_for_coalesce = {} for i in range(len(grad_param_segments) - 1, -1, -1): # We separate the insertion of coalesce op and the insertion of sync/allreduce op, # since that the coalesce op's insertion may invalidate the outputs_name_to_idx grad_segment, param_segment = grad_param_segments[i] before_idx = len(block.ops) for grad in outputs_name_to_idx: before_idx = min(before_idx, outputs_name_to_idx[grad][0]) pos_for_coalesce[i] = before_idx # insert the coalesce op based on the sorted before_idx pos_for_coalesce = sorted(pos_for_coalesce.items(), key=lambda kv: (kv[1], kv[0]), reverse=True) for i, before_idx in pos_for_coalesce: grad_segment, param_segment = grad_param_segments[i] fused_var = fused_vars[i] block._insert_op_without_sync(before_idx, type="coalesce_tensor", inputs={"Input": param_segment}, outputs={ "Output": grad_segment, "FusedOutput": fused_var }, attrs={ "copy_data": False, "use_align": True, "dtype": grad_segment[0].dtype, OP_ROLE_KEY: OpRole.Backward }) if self.calc_comm_same_stream: block._sync_with_cpp() return # insert the sync comm op for idx, op in enumerate(block.ops): if is_optimizer_op(op): block._insert_op_without_sync(idx, type='c_sync_comm_stream', inputs={'X': fused_vars}, outputs={'Out': fused_vars}, attrs={ 'ring_id': ring_id, OP_ROLE_KEY: OpRole.Backward }) break block._sync_with_cpp() def __get_ouputs_name_to_idx(self, first_backward_idx, block): # Each item of outputs_name_to_idx is a pair of idx. # The first entry of this pair is the idx of the first op generates the grad, # which is used to indicate the position to insert coalesce op. # The second entry of this pair is the idx of the last op generates the grad, # which is used to indicate the position to insert sync and allreduce op. outputs_name_to_idx = {} for idx in range(first_backward_idx, len(block.ops)): op = block.ops[idx] if is_optimizer_op(op): break for name in op.output_arg_names: if name == core.kEmptyVarName(): continue var = block.var(name) if not outputs_name_to_idx.get(var): # if the grad only be generated by one op # the first idx and the last ids are identical outputs_name_to_idx[var] = (idx, idx) else: outputs_name_to_idx[var] = (outputs_name_to_idx[var][0], idx) return outputs_name_to_idx