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From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Ingo Molnar <mingo@elte.hu>
Subject: Re: [stable] 2.6.23 regression: top displaying 9999% CPU usage
Date: Mon, 29 Oct 2007 21:33:48 +0100
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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>
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Am Montag, 29. Oktober 2007 schrieb Ingo Molnar:
> i've got a patch from Peter queued up. (see below) This should fix the 
> main issue.
[...]
> --- linux.orig/fs/proc/array.c
> +++ linux/fs/proc/array.c
> @@ -358,7 +358,8 @@ static cputime_t task_utime(struct task_
>  	}
>  	utime = (clock_t)temp;
> 
> -	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?

Christian