linux-kernel - Re: [patch] CFS scheduler, -v19

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Message-ID: <20070717171643.GB7905@elte.hu>
Date:	Tue, 17 Jul 2007 19:16:43 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Ian Kent <raven@...maw.net>
Cc:	Chuck Ebbert <cebbert@...hat.com>,
	Bill Davidsen <davidsen@....com>, linux-kernel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [patch] CFS scheduler, -v19


* Ian Kent <raven@...maw.net> wrote:

> > 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++;
> 
> OK, I'm with you, hi-res timer.
> But even so, how is the time in the past after adding a second.
> 
> Is it because I'm not setting tv_nsec when it's close to a second 
> boundary, and hence your recommendation above?

yeah, it looks a bit suspicious: you create a +1 second timeout out of a 
1 second resolution timesource. I dont yet understand the failure mode 
though that results in that looping and in the 30% CPU time use - do you 
understand it perhaps? (and automount is still functional while this is 
happening, correct?)

	Ingo
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