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Date: Tue, 17 Jul 2007 09:45:37 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Ian Kent <raven@themaw.net>
Cc: Chuck Ebbert <cebbert@redhat.com>, Bill Davidsen <davidsen@tmr.com>,
       linux-kernel@vger.kernel.org,
       Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [patch] CFS scheduler, -v19
Message-ID: <20070717074537.GA13539@elte.hu>
References: <20070706173319.GA2356@elte.hu> <1184054902.12336.19.camel@Homer.simpson.net> <469512C1.6090406@tmr.com> <20070711205556.GA27266@elte.hu> <4697EC49.4070303@tmr.com> <469BE462.9030004@redhat.com> <20070716215541.GA27171@elte.hu> <1184648474.3188.33.camel@raven.themaw.net>
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* Ian Kent <raven@themaw.net> wrote:

> Yes it does and I have two reported bugs so far.
> 
> In several places I have code similar to:
> 
> wait.tv_sec = time(NULL) + 1;
> wait.tv_nsec = 0;
> 
> signaled = 0;
> while (!signaled) {
>         status = pthread_cond_timedwait(&cond, &mutex, &wait);
>        if (status) {
>              if (status == ETIMEDOUT)
>                   break;
>              fatal(status);
>       }
> }

ah! It passes in a low-res time source into a high-res time interface 
(pthread_cond_timedwait()). Could you change the time(NULL) + 1 to 
time(NULL) + 2, or change it to:

	gettimeofday(&wait, NULL);
	wait.tv_sec++;

does this solve the spinning?

i'm wondering how widespread this is. If automount is the only app doing 
this then _maybe_ we could get away with it by changing automount?

	Ingo