From: Andy Lutomirski <luto@amacapital.net>
To: Jason Baron <jbaron@akamai.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Al Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Eric Wong <normalperson@yhbt.net>,
Davide Libenzi <davidel@xmailserver.org>,
Michael Kerrisk-manpages <mtk.manpages@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>
Subject: Re: [PATCH v2 0/2] Add epoll round robin wakeup mode
Date: Tue, 17 Feb 2015 11:46:14 -0800 [thread overview]
Message-ID: <CALCETrWAH7SbQm0T+_7wviiU6pJ0isBdWE-cQBGk-joAx2OzFw@mail.gmail.com> (raw)
In-Reply-To: <cover.1424200151.git.jbaron@akamai.com>
On Tue, Feb 17, 2015 at 11:33 AM, Jason Baron <jbaron@akamai.com> wrote:
> When we are sharing a wakeup source among multiple epoll fds, we end up with
> thundering herd wakeups, since there is currently no way to add to the
> wakeup source exclusively. This series introduces 2 new epoll flags,
> EPOLLEXCLUSIVE for adding to a wakeup source exclusively. And EPOLLROUNDROBIN
> which is to be used in conjunction to EPOLLEXCLUSIVE to evenly
> distribute the wakeups. This patch was originally motivated by a desire to
> improve wakeup balance and cpu usage for a listen socket() shared amongst
> multiple epoll fd sets.
>
> See: http://lwn.net/Articles/632590/ for previous test program and testing
> resutls.
>
> Epoll manpage text:
>
> EPOLLEXCLUSIVE
> Provides exclusive wakeups when attaching multiple epoll fds to a
> shared wakeup source. Must be specified with an EPOLL_CTL_ADD operation.
>
> EPOLLROUNDROBIN
> Provides balancing for exclusive wakeups when attaching multiple epoll
> fds to a shared wakeup soruce. Depends on EPOLLEXCLUSIVE being set and
> must be specified with an EPOLL_CTL_ADD operation.
>
> Thanks,
What permissions do you need on the file descriptor to do this? This
will be the first case where a poll-like operation has side effects,
and that's rather weird IMO.
--Andy
>
> -Jason
>
>
> Jason Baron (2):
> sched/wait: add round robin wakeup mode
> epoll: introduce EPOLLEXCLUSIVE and EPOLLROUNDROBIN
>
> fs/eventpoll.c | 25 ++++++++++++++++++++-----
> include/linux/wait.h | 11 +++++++++++
> include/uapi/linux/eventpoll.h | 6 ++++++
> kernel/sched/wait.c | 10 ++++++++--
> 4 files changed, 45 insertions(+), 7 deletions(-)
>
> --
> 1.8.2.rc2
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-api" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Andy Lutomirski
AMA Capital Management, LLC
next prev parent reply other threads:[~2015-02-17 19:46 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-17 19:33 [PATCH v2 0/2] Add epoll round robin wakeup mode Jason Baron
2015-02-17 19:33 ` [PATCH v2 1/2] sched/wait: add " Jason Baron
2015-02-17 19:33 ` [PATCH v2 2/2] epoll: introduce EPOLLEXCLUSIVE and EPOLLROUNDROBIN Jason Baron
2015-02-18 8:07 ` Ingo Molnar
2015-02-18 15:42 ` Jason Baron
2015-02-18 16:33 ` Ingo Molnar
2015-02-18 17:38 ` Jason Baron
2015-02-18 17:45 ` Ingo Molnar
2015-02-18 17:51 ` Ingo Molnar
2015-02-18 22:18 ` Eric Wong
2015-02-19 3:26 ` Jason Baron
2015-02-22 0:24 ` Eric Wong
2015-02-25 15:48 ` Jason Baron
2015-02-18 23:12 ` Andy Lutomirski
[not found] ` <CAPh34mcPNQELwZCDTHej+HK=bpWgJ=jb1LeCtKoUHVgoDJOJoQ@mail.gmail.com>
2015-02-27 22:24 ` Jason Baron
2015-02-17 19:46 ` Andy Lutomirski [this message]
2015-02-17 20:33 ` [PATCH v2 0/2] Add epoll round robin wakeup mode Jason Baron
2015-02-17 21:09 ` Andy Lutomirski
2015-02-18 3:15 ` Jason Baron
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