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Date: Mon, 29 Oct 2007 21:41:16 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: 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>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [stable] 2.6.23 regression: top displaying 9999% CPU usage
Message-ID: <20071029204116.GA13026@elte.hu>
References: <200710122231.50739.elendil@planet.nl> <4725D2A5.1050908@linux.vnet.ibm.com> <20071029200425.GA830@elte.hu> <200710292133.48125.borntraeger@de.ibm.com>
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* 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?

	Ingo