linux-kernel - Re: [REGRESSION] High, likely incorrect process cpu usage counters with kvm and 2.6.2[67]

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <48BBB2FF.9040104@qumranet.com>
Date:	Mon, 01 Sep 2008 12:16:47 +0300
From:	Avi Kivity <avi@...ranet.com>
To:	Parag Warudkar <parag.lkml@...il.com>
CC:	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Ingo Molnar <mingo@...e.hu>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	KVM list <kvm@...r.kernel.org>
Subject: Re: [REGRESSION] High, likely incorrect process cpu usage counters
 with kvm and 2.6.2[67]

Parag Warudkar wrote:
> On Sun, Aug 31, 2008 at 11:43 AM, Avi Kivity <avi@...ranet.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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/