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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Ingo Molnar <mingo@elte.hu>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>,
	Balbir Singh <balbir@linux.vnet.ibm.com>,
	Frans Pop <elendil@planet.nl>, Chuck Ebbert <cebbert@redhat.com>,
	Greg KH <greg@kroah.com>,
	stable@kernel.org, linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [stable] 2.6.23 regression: top displaying 9999% CPU usage
Date: Mon, 29 Oct 2007 22:11:04 +0100	[thread overview]
Message-ID: <1193692264.5644.82.camel@lappy> (raw)
In-Reply-To: <20071029204116.GA13026@elte.hu>


On Mon, 2007-10-29 at 21:41 +0100, Ingo Molnar wrote:
> * Christian Borntraeger <borntraeger@de.ibm.com> wrote:
> 
> > > -	return clock_t_to_cputime(utime);
> > > +	p->prev_utime = max(p->prev_utime, clock_t_to_cputime(utime));
> > > +	return p->prev_utime;
> > >  }
> > [...]
> > 
> > I dont think it will work. It will make utime monotic, but stime can 
> > still decrease. For example let sum_exec_runtime increase by a tiny 
> > little bit while utime will get a full additional tick. stime is 
> > sum-utime. So stime can still go backwards. So I think that we need 
> > this kind of logic for stime as well, no?
> 
> yeah, probably. Peter?

/me dons the brown paper bag while mumbling an agreement of sorts.

I'll not attempt to come up with a patch as I fear I'll just make a
bigger mess in my current state, hope to feel better tomorrow..


  reply	other threads:[~2007-10-29 21:12 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-12 20:31 2.6.23 regression: top displaying 9999% CPU usage Frans Pop
2007-10-12 21:22 ` [stable] " Greg KH
2007-10-13  7:53   ` Frans Pop
2007-10-14 20:36     ` Christian Borntraeger
2007-10-16  8:29       ` Christian Borntraeger
2007-10-16  9:30         ` Balbir Singh
2007-10-16 10:11           ` Frans Pop
2007-10-16 10:38             ` Balbir Singh
2007-10-16 10:34           ` Christian Borntraeger
2007-10-16 12:59             ` Balbir Singh
2007-10-29 12:05               ` Frans Pop
2007-10-29 12:31                 ` Balbir Singh
2007-10-29 20:04                   ` Ingo Molnar
2007-10-29 20:33                     ` Christian Borntraeger
2007-10-29 20:41                       ` Ingo Molnar
2007-10-29 21:11                         ` Peter Zijlstra [this message]
2007-10-29 21:22                         ` Frans Pop
2007-10-29 21:43                     ` Balbir Singh
2007-10-29 23:19                       ` Frans Pop
2007-10-29 23:22                         ` Ingo Molnar
2007-10-30 20:22                           ` Otavio Salvador
2007-10-29 23:24                         ` Balbir Singh
2007-10-30  5:56                       ` Christian Borntraeger
2007-10-30  6:00                         ` Balbir Singh

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