How to determine whether nginx uses epoll

Question

nginx documentation says that the appropriate method can be automatically selected:

There is normally no need to specify it explicitly, because nginx will by default use the most efficient method.

Use epoll is not specified in the configuration file. How to determine whether nginx uses epoll?

Answer 1

Download the source code and log
Compile your own version orz

In fact, just compile a version that can be debugged by gdb, and then use gdb to start it, and you can track and see where nginx is blocked when no events arrive (whether it is blocked in the epoll event processing function

For specific tools and methods, please refer to "In-depth Analysis of Nginx" written by Chinese people

Answer 2

Linux versions above 2.6 should all support epoll.

You can use strace to check whether nginx calls the epoll series syscall

Answer 3

The default is epoll, in the Linux version