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Paddle/paddle/fluid/framework/details/build_strategy.h

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// Copyright (c) 2018 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.
#pragma once
#include <string>
namespace paddle {
namespace framework {
namespace details {
struct BuildStrategy {
// ParallelExecutor supports two modes of ReduceStrategy, kAllReduce and
// kReduce, for CPU and GPU. If you use kAllReduce, different threads
// optimize their parameters separately. If you use kReduce, the optimizations
// of parameters are distributed to different threads.
// For example, a model has 100 parameters and is running with four threads,
// if you choose kAllReduce, every thread is to optimize 100 parameters
// separately, if you choose kReduce, every thread is to optimize 25
// parameters.
// Of particular note is, if you use kReduce when using CPU training,
// all the parameters are shared between different threads. This feature will
// save memory.
// FIXME(zcd): The result of the two modes(kAllReduce and kReduce) maybe not
// equal for GPU. Because, the result of the different order of summing maybe
// different, for example, the result of `a+b+c+d` may be different with the
// result of `c+a+b+d`.
// For GPU, the implementation of kAllReduce and kReduce is adopted NCCL,
// so the result of kAllReduce and kReduce maybe not equal.
// For CPU, if you want to fix the order of summing to make the result
// of kAllReduce and kReduce no diff, you can add
// `FLAGS_cpu_deterministic=true` to env.
enum class ReduceStrategy { kAllReduce = 0, kReduce = 1 };
enum class GradientScaleStrategy {
kCoeffNumDevice = 0,
kOne = 1,
kCustomized = 2,
};
ReduceStrategy reduce_{ReduceStrategy::kAllReduce};
GradientScaleStrategy gradient_scale_{GradientScaleStrategy::kCoeffNumDevice};
std::string debug_graphviz_path_{""};
bool enable_data_balance_{false};
};
} // namespace details
} // namespace framework
} // namespace paddle