7 ms·

I think the authors want to avoid thundering herd. You can find this basic pattern in the book UNIX Network Programming.

• rdtsc 11y ago
  Hmm, thought that was fixed 10 years ago or so. I can't believe the standard accept() call will wake up all threads on a modern Linux kernel. Maybe if it is using epoll/select/etc. it would exhibit the thundering herd issue.
• jvink 11y ago
  Correct. The accepting socket is shared between multiple workers which each have its own fd for epoll or kqueue. Because of this a form of serialising the accepts between said workers is needed to avoid unnecessary wakeups.
  • rdtsc 11y ago
    Actually that is being changed: http://lwn.net/Articles/633422/ http://lwn.net/Articles/633422/ See part about EPOLLEXCLUSIVE
    • jvink 11y ago
      That is great, thanks for sharing.
      • rdtsc 11y ago
        If you are the author, thanks for sharing the project. You did a great job and made the right choice of having per CPU worker processes each with their own epoll loop.