accpet_mutex cause nginx worker balance problem

[xinghua_hi]

hello，

       I still can't understand why accept_mutex cause disbalance. In code
below, multi worker will try to get mutex and the question is ,  why one
worker can always get the mutex ? I  test many times,  find that one worker
can always accept new connection much more than others. Thanks very much.

      if (ngx_use_accept_mutex) {
        if (ngx_accept_disabled > 0) {
            ngx_accept_disabled--;

        } else {
            if (ngx_trylock_accept_mutex(cycle) == NGX_ERROR) {
                return;
            }

            if (ngx_accept_mutex_held) {
                flags |= NGX_POST_EVENTS;

            } else {
                if (timer == NGX_TIMER_INFINITE
                    || timer > ngx_accept_mutex_delay)
                {
                    timer = ngx_accept_mutex_delay;
                }
            }
        }
    }

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,252241,252254#msg-252254