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From: Hagen Paul Pfeifer <hagen@jauu.net>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Li Yu <raise.sail@gmail.com>,
	linux-kernel@vger.kernel.org, davidel@xmailserver.org
Subject: Re: The thundering herd like problem when multi epolls on one fd
Date: Sat, 14 Jan 2012 16:57:13 +0100	[thread overview]
Message-ID: <20120114155713.GA2966@hell> (raw)
In-Reply-To: <1326547247.5287.19.camel@edumazet-laptop>

* Eric Dumazet | 2012-01-14 14:20:47 [+0100]:

>What happens if the awaken thread does not consume the event, and prefer
>to exit ?
>
>If several threads are doing select()/poll()/epoll() on a shared fd,
>they _all_ must be notified the fd is ready, as manpages claim.
>

And if it is intended? Signaled via a new epoll_ctl() epoll_event flag? E.g.
EPOLLEXCLUSIVE

>Doing otherwise would require the prior consent of the user, using a
>special flag for example, and documentation.

Oops, yes. A fanout like mechanism _may be_ superior, but I think tests will
show some improvements anyway.

Hagen

  reply	other threads:[~2012-01-14 15:57 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-14 11:13 The thundering herd like problem when multi epolls on one fd Li Yu
2012-01-14 13:20 ` Eric Dumazet
2012-01-14 15:57   ` Hagen Paul Pfeifer [this message]
  -- strict thread matches above, loose matches on Subject: below --
2012-01-15 15:41 Li Yu

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