macOS 10.13.2 占用cpu高，一直在50%以上 下面是截图 <img width="626" alt="01" src="https://user-images.githubusercontent.com/16211479/34934067-0c57474e-fa14-11e7-9f1e-45b50387ffd0.png"> <img width="566" alt="02" src="https://user-images.githubusercontent.com/16211479/34934071-0e1cd2b0-fa14-11e7-85a9-402c7572b806.png">
