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From: Avi Kivity <avi@qumranet.com>
To: Parag Warudkar <parag.lkml@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Ingo Molnar <mingo@elte.hu>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	KVM list <kvm@vger.kernel.org>
Subject: Re: [REGRESSION] High, likely incorrect process cpu usage counters with kvm and 2.6.2[67]
Date: Mon, 01 Sep 2008 12:16:47 +0300	[thread overview]
Message-ID: <48BBB2FF.9040104@qumranet.com> (raw)
In-Reply-To: <f7848160808311109v70db1e99hb6af3b89c34d0d8c@mail.gmail.com>

Parag Warudkar wrote:
> On Sun, Aug 31, 2008 at 11:43 AM, Avi Kivity <avi@qumranet.com> wrote:
>   
>> Running an idle Windows VM on Linux 2.6.26+ with kvm, one sees high values
>> for the kvm process in top (30%-70% cpu), where one would normally expect
>> 0%-1%.  Surprisingly, the per-cpu system counters show almost 100% idle,
>> leading me to believe this is an accounting error and that the process does
>> not actually consume this much cpu.
>>     
>
> Busted process accounting - This looks the same as
> http://bugzilla.kernel.org/show_bug.cgi?id=11209 .
> Please verify. Peter's patch in latest git stops showing "incorrect
> looking" CPU usage but at least the process times are still wrong,
> horribly.
> In fact the CPU usage thing in -rc5 is likely also incorrect but I
> need to analyze that bit a little more.
>
> From Today's Git -
>
> PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
>
> 12961 parag     20   0 83000 8908 6628 R    0  0.1  5124415h npviewer.bin
>
>   

Yes, it looks very similar.  In my tests, %CPU is consistent with TIME; 
it's just not consistent with what's actually happening and with the 
global statistics.


-- 
error compiling committee.c: too many arguments to function


  reply	other threads:[~2008-09-01  9:17 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-31 15:43 [REGRESSION] High, likely incorrect process cpu usage counters with kvm and 2.6.2[67] Avi Kivity
2008-08-31 18:09 ` Parag Warudkar
2008-09-01  9:16   ` Avi Kivity [this message]
2008-09-01 14:58 ` [PATCH] sched_clock: fix NOHZ interaction Peter Zijlstra
2008-09-01 16:17   ` Avi Kivity
2008-09-05 16:13     ` Ingo Molnar

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