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

From: Martin Schwidefsky
Date: Wed Sep 09 2009 - 04:02:58 EST


On Tue, 8 Sep 2009 22:58:58 -0700
Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Fri, 14 Aug 2009 13:18:08 +0100 (BST) Michael Abbott <michael@xxxxxxxxxxxxxxx> 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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