linux-kernel - Re: strange high system cpu usage.

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Message-Id: <20070330035457.57A4124753@ws5-3.us4.outblaze.com>
Date:	Fri, 30 Mar 2007 11:54:57 +0800
From:	"Elliott Johnson" <ejohnson@...uxmail.org>
To:	linux-kernel@...r.kernel.org
Subject: Re: strange high system cpu usage.

>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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