httpd-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Luca Toscano <>
Subject Re: Frequent wake-ups for mpm_event
Date Fri, 05 Aug 2016 12:58:39 GMT
2016-08-04 17:56 GMT+02:00 Luca Toscano <>:

> Hi Apache Devs,
> there is an interesting bugzilla ticket about mpm_event and frequent
> wake-ups:
> Would it be possible to avoid them adding APR_POLLSET_WAKEABLE to the
> event_pollset flags and calling apr_pollset_wakeup right after
> apr_skiplist_insert?
> I might have completely misunderstood the code, but I wanted to bring up
> the issue to have more expert opinions from the list. The skiplist use case
> is still a bit unclear to me even if we discussed it a while ago in another
> email thread.

 Very high level idea:

Remarks from APR:

 * @remark If flags contains APR_POLLSET_WAKEABLE, then a pollset is
 *         created with additional internal pipe object used for the
 *         apr_pollset_wakeup() call. The actual size of pollset is
 *         in that case size + 1. This feature is only supported on some
 *         platforms; the apr_pollset_create_ex() call will fail with
 *         APR_ENOTIMPL on platforms where it is not supported.

Moreover for apr_pollset_wakeup: "If the pollset was not created with
APR_POLLSET_WAKEABLE the return value is APR_EINIT."

This is only an idea of course, I am probably missing a lot of pieces, but
let me know if you have any feedback.



View raw message