From: Ingo Molnar <mingo@elte.hu>
To: David Schwartz <davids@webmaster.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Network slowdown due to CFS
Date: Tue, 2 Oct 2007 08:08:48 +0200 [thread overview]
Message-ID: <20071002060848.GB18588@elte.hu> (raw)
In-Reply-To: <MDEHLPKNGKAHNMBLJOLKOEOBHCAC.davids@webmaster.com>
* David Schwartz <davids@webmaster.com> wrote:
> > (user-space spinlocks are broken beyond words for anything but
> > perhaps SCHED_FIFO tasks.)
>
> User-space spinlocks are broken so spinlocks can only be implemented
> in kernel-space? Even if you use the kernel to schedule/unschedule the
> tasks, you still have to spin in user-space.
user-space spinlocks (in anything but SCHED_FIFO tasks) are pretty
broken because they waste CPU time. (not as broken as yield, because
"wasting CPU time" is a more deterministic act, but still broken) Could
you cite a single example where user-space spinlocks are technically the
best solution?
Ingo
next prev parent reply other threads:[~2007-10-02 6:08 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-26 8:52 Network slowdown due to CFS Martin Michlmayr
2007-09-26 9:34 ` Ingo Molnar
2007-09-26 9:47 ` Ingo Molnar
2007-09-26 10:08 ` Martin Michlmayr
2007-09-26 10:18 ` Ingo Molnar
2007-09-26 10:20 ` Mike Galbraith
2007-09-26 10:23 ` Mike Galbraith
2007-09-26 10:48 ` Martin Michlmayr
2007-09-26 11:21 ` Ingo Molnar
2007-09-26 11:29 ` Martin Michlmayr
2007-09-26 12:00 ` David Schwartz
2007-09-26 13:31 ` Ingo Molnar
2007-09-26 15:40 ` Stephen Hemminger
2007-09-26 15:46 ` Stephen Hemminger
2007-09-27 9:30 ` Jarek Poplawski
2007-09-27 9:46 ` Ingo Molnar
2007-09-27 12:27 ` Jarek Poplawski
2007-09-27 13:31 ` Ingo Molnar
2007-09-27 14:42 ` Jarek Poplawski
2007-09-28 6:10 ` Nick Piggin
2007-10-01 8:43 ` Jarek Poplawski
2007-10-01 16:25 ` Ingo Molnar
2007-10-01 16:49 ` David Schwartz
2007-10-01 17:31 ` Ingo Molnar
2007-10-01 18:23 ` David Schwartz
2007-10-02 6:06 ` Ingo Molnar
2007-10-02 6:47 ` Andi Kleen
2007-10-03 8:02 ` Jarek Poplawski
2007-10-03 8:16 ` Ingo Molnar
2007-10-03 8:56 ` Jarek Poplawski
2007-10-03 9:10 ` Ingo Molnar
2007-10-03 9:50 ` Jarek Poplawski
2007-10-03 10:55 ` Dmitry Adamushko
2007-10-03 10:58 ` Dmitry Adamushko
2007-10-03 11:20 ` Jarek Poplawski
2007-10-03 11:22 ` Ingo Molnar
2007-10-03 11:40 ` Jarek Poplawski
2007-10-03 11:56 ` yield Ingo Molnar
2007-10-03 12:16 ` yield Jarek Poplawski
2007-10-07 7:18 ` Network slowdown due to CFS Ingo Molnar
2007-10-04 5:33 ` Casey Dahlin
2007-10-02 6:08 ` Ingo Molnar [this message]
2007-10-02 6:26 ` Ingo Molnar
2007-10-02 6:46 ` yield API Ingo Molnar
2007-10-02 11:50 ` linux-os (Dick Johnson)
2007-10-02 15:24 ` Douglas McNaught
2007-10-02 21:57 ` Eric St-Laurent
2007-12-12 22:39 ` Jesper Juhl
2007-12-13 4:43 ` Kyle Moffett
2007-12-13 20:10 ` David Schwartz
2007-10-01 19:53 ` Network slowdown due to CFS Arjan van de Ven
2007-10-01 22:17 ` David Schwartz
2007-10-01 22:35 ` Arjan van de Ven
2007-10-01 22:44 ` David Schwartz
2007-10-01 22:55 ` Arjan van de Ven
2007-10-02 15:37 ` David Schwartz
2007-10-03 7:15 ` Jarek Poplawski
2007-10-03 11:31 ` Helge Hafting
2007-10-04 0:31 ` Rusty Russell
2007-10-01 16:55 ` Chris Friesen
2007-10-01 17:09 ` Ingo Molnar
2007-10-01 17:45 ` Chris Friesen
2007-10-01 19:09 ` iperf yield usage Ingo Molnar
2007-10-02 9:03 ` Network slowdown due to CFS Jarek Poplawski
2007-10-02 13:39 ` Jarek Poplawski
2007-10-02 9:26 ` Jarek Poplawski
2007-09-27 9:49 ` Ingo Molnar
2007-09-27 10:54 ` Martin Michlmayr
2007-09-27 10:56 ` Ingo Molnar
2007-09-27 11:12 ` Martin Michlmayr
-- strict thread matches above, loose matches on Subject: below --
2007-10-01 22:27 Hubert Tonneau
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