From: Thomas Gleixner <tglx@linutronix.de>
To: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Ulrich Drepper <drepper@gmail.com>,
Maximilian Engelhardt <maxi@daemonizer.de>,
Michael Buesch <mb@bu3sch.de>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-wireless <linux-wireless@vger.kernel.org>,
Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
Jeff Garzik <jgarzik@pobox.com>,
Gary Zambrano <zambrano@broadcom.com>,
netdev@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>
Subject: Re: iperf: performance regression (was b44 driver problem?)
Date: Mon, 04 Jun 2007 21:00:47 +0200 [thread overview]
Message-ID: <1180983647.4404.38.camel@chaos> (raw)
In-Reply-To: <20070604105158.31ede1f5@freepuppy>
On Mon, 2007-06-04 at 10:51 -0700, Stephen Hemminger wrote:
> > I doubt that. This is in the iperf code itself.
> >
> > void thread_rest ( void ) {
> > #if defined( HAVE_THREAD )
> > #if defined( HAVE_POSIX_THREAD )
> > // TODO add checks for sched_yield or pthread_yield and call that
> > // if available
> > usleep( 0 );
> >
> > ----------^^^^
> >
> > It results in a nanosleep({0,0}, NULL)
> >
> > tglx
> >
>
> Yes, the following patch makes iperf work better than ever.
> But are other broken applications going to have same problem.
> Sounds like the old "who runs first" fork() problems.
Not really. The fork() "who runs first" problem is nowhere specified.
usleep(0) is well defined:
.... If the value of useconds is 0, then the call has no effect.
So the call into the kernel has been wrong for quite a time.
tglx
next prev parent reply other threads:[~2007-06-04 19:01 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-26 0:24 b44: regression in 2.6.22 Stephen Hemminger
2007-05-26 3:51 ` Gary Zambrano
2007-05-26 17:01 ` Michael Buesch
[not found] ` <200705261901.18110.mb-fseUSCV1ubazQB+pC5nmwQ@public.gmane.org>
2007-05-27 19:25 ` b44: regression in 2.6.22 (resend) Maximilian Engelhardt
[not found] ` <200705272125.25506.maxi-OwNUvPV92VfddJNmlsFzeA@public.gmane.org>
2007-05-27 19:45 ` Michael Buesch
[not found] ` <200705272145.00796.mb-fseUSCV1ubazQB+pC5nmwQ@public.gmane.org>
2007-05-27 20:36 ` Maximilian Engelhardt
[not found] ` <200705272236.42628.maxi-OwNUvPV92VfddJNmlsFzeA@public.gmane.org>
2007-05-27 20:46 ` Michael Buesch
[not found] ` <200705272246.16960.mb-fseUSCV1ubazQB+pC5nmwQ@public.gmane.org>
2007-05-27 21:46 ` Maximilian Engelhardt
2007-05-27 21:13 ` Michael Buesch
2007-05-27 21:16 ` Michael Buesch
[not found] ` <200705272316.07338.mb-fseUSCV1ubazQB+pC5nmwQ@public.gmane.org>
2007-05-27 21:50 ` Maximilian Engelhardt
[not found] ` <200705272313.33129.mb-fseUSCV1ubazQB+pC5nmwQ@public.gmane.org>
2007-05-27 22:15 ` Maximilian Engelhardt
2007-05-28 0:24 ` Michael Buesch
[not found] ` <200705280224.40506.mb-fseUSCV1ubazQB+pC5nmwQ@public.gmane.org>
2007-05-28 0:40 ` Maximilian Engelhardt
[not found] ` <200705280240.17910.maxi-OwNUvPV92VfddJNmlsFzeA@public.gmane.org>
2007-05-28 10:16 ` Michael Buesch
[not found] ` <200705281216.51690.mb-fseUSCV1ubazQB+pC5nmwQ@public.gmane.org>
2007-05-28 14:09 ` Maximilian Engelhardt
[not found] ` <200705281609.49859.maxi-OwNUvPV92VfddJNmlsFzeA@public.gmane.org>
2007-05-28 15:14 ` Michael Buesch
[not found] ` <200705281714.25841.mb-fseUSCV1ubazQB+pC5nmwQ@public.gmane.org>
2007-05-28 15:32 ` Thomas Gleixner
2007-05-28 15:43 ` Michael Buesch
2007-05-28 17:44 ` Maximilian Engelhardt
2007-05-28 19:23 ` Thomas Gleixner
2007-05-28 20:55 ` Maximilian Engelhardt
2007-05-28 21:45 ` Thomas Gleixner
2007-05-29 18:28 ` Maximilian Engelhardt
[not found] ` <200705282255.56490.maxi-OwNUvPV92VfddJNmlsFzeA@public.gmane.org>
2007-05-29 13:58 ` Gary Zambrano
[not found] ` <1180447123.17146.4.camel-opBMJL+S1+nCw/J+WP9nZ0NK2P1VvzQgpWgKQ6/u3Fg@public.gmane.org>
2007-05-29 17:23 ` Maximilian Engelhardt
2007-06-03 16:26 ` Maximilian Engelhardt
[not found] ` <200706031826.06891.maxi-OwNUvPV92VfddJNmlsFzeA@public.gmane.org>
2007-06-04 6:39 ` Thomas Gleixner
2007-06-04 16:09 ` Stephen Hemminger
2007-06-04 16:35 ` Thomas Gleixner
2007-06-04 16:59 ` iperf: performance regression (was b44 driver problem?) Stephen Hemminger
2007-06-04 17:32 ` Thomas Gleixner
2007-06-04 17:51 ` Stephen Hemminger
2007-06-04 19:00 ` Thomas Gleixner [this message]
2007-06-04 19:26 ` Thomas Gleixner
2007-06-04 19:32 ` Ingo Molnar
2007-06-04 19:47 ` Maximilian Engelhardt
2007-06-04 20:02 ` Stephen Hemminger
2007-06-04 20:52 ` Maximilian Engelhardt
2007-05-28 10:49 ` b44: regression in 2.6.22 (resend) Michael Buesch
[not found] ` <200705281249.56106.mb-fseUSCV1ubazQB+pC5nmwQ@public.gmane.org>
2007-05-28 14:12 ` Maximilian Engelhardt
2007-05-28 14:55 ` Michael Buesch
2007-05-29 14:14 ` Gary Zambrano
[not found] ` <1180448075.17146.12.camel-opBMJL+S1+nCw/J+WP9nZ0NK2P1VvzQgpWgKQ6/u3Fg@public.gmane.org>
2007-05-29 20:45 ` Michael Buesch
[not found] ` <200705292245.22940.mb-fseUSCV1ubazQB+pC5nmwQ@public.gmane.org>
2007-05-29 21:01 ` Stephen Hemminger
2007-05-29 21:05 ` Gary Zambrano
[not found] ` <1180472741.17711.19.camel-opBMJL+S1+nCw/J+WP9nZ0NK2P1VvzQgpWgKQ6/u3Fg@public.gmane.org>
2007-05-29 22:39 ` Jeff Garzik
[not found] ` <465CABA3.10003-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
2007-05-29 21:36 ` Gary Zambrano
2007-05-30 10:45 ` Michael Buesch
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