Don't you need a polling loop to see when a request is finished?

难道不需要进行轮询循环就能查看何时完成请求吗？

youdao

If poll is called in a loop, these expensive system calls involved in polling can dramatically affect the overall performance when a large number of file descriptors are monitored.

在监视大量文件描述符时，如果在循环中调用poll ，poll所涉及的这些高成本的系统调用会严重影响总体性能。

youdao

If poll is called in a loop, these expensive system calls involved in polling can dramatically affect the overall performance when a large number of file descriptors are monitored.

在监视大量文件描述符时，如果在循环中调用poll ，poll所涉及的这些高成本的系统调用会严重影响总体性能。

youdao