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From: Jason Baron <jbaron@akamai.com>
To: peterz@infradead.org, mingo@redhat.com, viro@zeniv.linux.org.uk
Cc: akpm@linux-foundation.org, normalperson@yhbt.net,
	davidel@xmailserver.org, mtk.manpages@gmail.com,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-api@vger.kernel.org
Subject: [PATCH v2 0/2] Add epoll round robin wakeup mode
Date: Tue, 17 Feb 2015 19:33:36 +0000 (GMT)	[thread overview]
Message-ID: <cover.1424200151.git.jbaron@akamai.com> (raw)

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,

-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


             reply	other threads:[~2015-02-17 19:33 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-17 19:33 Jason Baron [this message]
2015-02-17 19:33 ` [PATCH v2 1/2] sched/wait: add round robin wakeup mode 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 ` [PATCH v2 0/2] Add epoll round robin wakeup mode Andy Lutomirski
2015-02-17 20:33   ` Jason Baron
2015-02-17 21:09     ` Andy Lutomirski
2015-02-18  3:15       ` Jason Baron

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