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Date:      Sat, 16 Aug 2008 18:33:39 +0100
From:      Chris Elsworth <chris@shagged.org>
To:        Won De Erick <won.derick@yahoo.com>
Cc:        freebsd-testing@freebsd.org, Jeremy Chadwick <koitsu@FreeBSD.org>, freebsd-performance@freebsd.org, freebsd-hardware@freebsd.org
Subject:   Re: CPU Utilization on IBM x3755
Message-ID:  <20080816173339.GA34116@thestra.telon.net>
In-Reply-To: <897559.10614.qm@web45814.mail.sp1.yahoo.com>
References:  <897559.10614.qm@web45814.mail.sp1.yahoo.com>

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On Sat, Aug 16, 2008 at 01:18:18AM -0700, Won De Erick wrote:
 
> >Regarding why you're adding up all the individual process statistics: I
> >can imagine they would vary a slight bit, but I cannot explain a 7%
> >variance.  Someone with more knowledge will have to assist there.
> 
> Though the header could be conclusive, I should want the specific processes (or threads). 
> And come up with a list of breakdowns, like:
> 
> Then match this by adding up all individual processes statistics. And if I couldn't match, at least I could tell some factors that cause variance.

At the bottom of man top, reformatted for email width:

	As with ps(1), things can change while top  is  collecting
	information for  an  update.  The picture it gives is only
	a close approximation to reality.

Could this explain the variations you are seeing? top never gives you
an accurate snapshot of what the system is doing at any one instant in
time, afaik.

-- 
Chris



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