Created by: anpark

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• 标题：paddle 大batchsize CPU正常，但是GPU bug, 性能比tf差480多倍
• 版本、环境信息：    1）PaddlePaddle版本：1.5.1    2）CPU：intel    3）GPU：k40    4）系统环境：linux centos 6.3, cuda 9.0, cudnn 7.0
• 训练信息    1）单机，单卡    2）显存信息 11G    3）Operator信息
• 复现信息：如为报错，请给出复现环境、复现步骤
• 问题描述：CPU版本正常，但是GPU慢很多，初步发现是sync 操作 卡住

Thank you for contributing to PaddlePaddle. Before submitting the issue, you could search issue in the github in case that there was a similar issue submitted or resolved before. If there is no solution,please make sure that this is a training issue including the following details: System information -PaddlePaddle version （eg.1.1）or CommitID -CPU: including CPUMKL/OpenBlas/MKLDNN version -GPU: including CUDA/CUDNN version -OS Platform (eg.Mac OS 10.14) -Other imformation: Distriuted training/informantion of operator/ Graphics card storage To Reproduce Steps to reproduce the behavior Describe your current behavior Code to reproduce the issue Other info / logs