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linux内核中的 unlikely()和 likely()

2011-04-13 13:26:25| 分类： Linux | 标签： |举报 |字号大中小订阅

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这是gcc的扩展，目的是增加条件分支预测的准确性，cpu会提前装载后面的指令，遇到条件转移指令时会提前预测并装载某个分支的指令。

unlikely表示你可以确认该条件是极少发生的，

相反

likely表示该条件多数情况下会发生。

编译器会产生相应的代码来优化cpu执行效率。

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