Re: Performance degradation in commit ac1d794

On 2016-03-18 05:56:41 -0400, Robert Haas wrote:
> >> 0 at the top of the loop and skip it forthwith if so.
> >
> > You mean in WaitEventSetWait()? There's
> >                 else if (rc == 0)
> >                 {
> >                         break;
> >                 }
> > which is the timeout case. There should never be any other case of
> >                 returning 0 elements?
> 
> No, I meant if (cur_event->events == 0) continue;

I'm not following. Why would there be an event without an empty event
mask? Ok, you can disable all notifications for a socket using
ModifyWaitEvent(), but that's not particularly common, right?  At least
for epoll, it'd not play a role anyway, since epoll_wait() will actually
return pointers to the elements we're waiting on; for windows we get the
offset in ->handles.  I guess we could do so in the select/poll case,
but adding another if for something infrequent doesn't strike me as a
great benefit.

- Andres