From: "Elliott Johnson" <ejohnson@linuxmail.org>
To: "Elliott Johnson" <ejohnson@linuxmail.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: strange high system cpu usage.
Date: Sat, 31 Mar 2007 10:08:37 +0800 [thread overview]
Message-ID: <20070331020837.C597743FCD@ws5-1.us4.outblaze.com> (raw)
Lee
Thanks for your help. In testing different kernels we found that using an unpatched kernel from kernel.org seems to fix the problem. I'm assuming that a patch added in the gentoo-sources patch set was creating the problem. Our once 8 minute untar is now down to 7-8 seconds with a vanilla 2.6.18.6 kernel.
If anyone is interested in our oprofile code or other info, just ask and I'll post it. Otherwise I'll be reporting this to the gentoo developers.
-E
> ----- Original Message -----
> From: "Elliott Johnson" <ejohnson@linuxmail.org>
> To: linux-kernel@vger.kernel.org
> Subject: Re: strange high system cpu usage.
> Date: Fri, 30 Mar 2007 11:54:57 +0800
>
>
> > What problem are you trying to solve? IOW, how do you know it's not
> > just an artifact of diferent load average calculation between 2.4 and
> > 2.6?
> >
> > Are you actually seeing reduced throughput/performance? Or are you
> > just looking at load average?
> >
> > Lee
>
> Well the problem is apparent, we are having abnormally high cpu
> usage. It's about a
> 20-40% performance hit.
>
> The load calculations were not between 2.4 and 2.6 kernel versions,
> but between 2.6.8 and
> 2.6.19. Sorry if this wasn't very clear from my last email.
>
> In trying to diagnose the problem I also looked at memory stats
> (vmstat) and found the
> 'buffered' memory statistic way off from the comparable debian
> (2.6.8) install (0-300kb
> versus 500mb).
>
> The vmstat man page has little information on this statistic and
> there seems to be varying
> explanations on the web. I was hoping for a decisive explanation
> (or link) and possibly
> advice in toggling this value (or reasons not to).
>
> I'm still trying to work on this at my end. Some recent tests show
> that it might be
> related to the megasas driver or the large number of small files we
> are using on a xfs
> formated 10T array. I'll keep at it.
>
> Thanks for your response,
>
> -Elliott
>
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next reply other threads:[~2007-03-31 2:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-31 2:08 Elliott Johnson [this message]
-- strict thread matches above, loose matches on Subject: below --
2007-03-30 3:54 Elliott Johnson
2007-03-30 4:39 ` Lee Revell
2007-03-29 22:22 Elliott Johnson
2007-03-30 2:14 ` Lee Revell
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