linux-kernel - Re: [PATCH] Re: /proc/uptime idle counter remains at 0

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Message-ID: <20090909100247.2acaceff@skybase>
Date:	Wed, 9 Sep 2009 10:02:47 +0200
From:	Martin Schwidefsky <schwidefsky@...ibm.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Michael Abbott <michael@...neidae.co.uk>,
	Jan Engelhardt <jengelh@...ozas.de>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Johan van Baarlen <JF@...baarlen.demon.nl>
Subject: Re: [PATCH] Re: /proc/uptime idle counter remains at 0

On Tue, 8 Sep 2009 22:58:58 -0700
Andrew Morton <akpm@...ux-foundation.org> wrote:

> On Fri, 14 Aug 2009 13:18:08 +0100 (BST) Michael Abbott <michael@...neidae.co.uk> wrote:
> 
> > Reviving this:
> > 
> > On Sat, 9 May 2009, Jan Engelhardt wrote:
> > > starting from v2.6.28-4930-g79741dd lasting thru at least v2.6.29.1,
> > > the second field of /proc/uptime always shows 0.00. This happens for
> > > both the typical i386 (my case) and on an ARM (according to Michael,
> > > cc'ed).
> > > 
> > > >From the commit log of 79741dd:
> > > 
> > > 	"""The cpu time spent by the idle process actually doing
> > > 	something is currently accounted as idle time. This is plain
> > > 	wrong, the architectures that support VIRT_CPU_ACCOUNTING=y
> > > 	can do better: distinguish between the time spent doing
> > > 	nothing and the time spent by idle doing work. The first is
> > > 	accounted with account_idle_time and the second with
> > > 	account_system_time."""
> > > 
> > > Citing Michael from our irc conversation:
> > > 
> > > 	"""the writer[committer] [says] that [the] idle process time
> > > 	isn't really idle time ... but that's all that /proc/uptime
> > > 	looks at. I guess fs/proc/uptime.c needs to catch up."""
> > > 
> > > So, were the updates to uptime.c missed, or do we now live on with
> > > /proc/uptime constantly having 0?
> > 
> > My previous patch seems to have run into the sand.  It every so nearly got 
> > pulled into mainstream as far as I can tell, but didn't seem to make it; 
> > no idea what happened.
> > 
> > So here we go again:
> > 
> 
> Imagine my surprise to find a version of this patch lurking in Martin's
> tree since June 22.  It's a regression fix!
> 
> Johan, does this patch help with the regression you reported in
> http://bugzilla.kernel.org/show_bug.cgi?id=14131 ?

I did send a Please-Pull for the cputime branch back in May. Seems like it
never has been pulled. I don't know why, so perhaps I should just retry. 


-- 
blue skies,
   Martin.

"Reality continues to ruin my life." - Calvin.

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