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Date: Thu, 29 Mar 2007 10:58:22 -0500
From: Eric Anderson <anderson@freebsd.org>
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To: Ivan Voras <ivoras@fer.hr>
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Cc: freebsd-geom@freebsd.org
Subject: Re: raid3 is slow
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On 03/29/07 10:52, Ivan Voras wrote:
> Dag-Erling Smørgrav wrote:
> 
>> You don't seem to understand what the load averages mean.  They are
>> the average number of runnable threads in the scheduler queue over the
>> last one, five and fifteen seconds.  Certain workloads will drive up
>> the load averages without consuming all available CPU time.  This is
>> particularly the case for workloads where small chunks of data (e.g.
>> RAID3 stripes) are passed around between multiple threads.
> 
> But, in his case the threads DO seem to consume much more CPU time than 
> they should - especially the g_down thread. In this case, load avg ( as 
> an approximation of real system load) is useful, and he's not concerned 
> without cause.
> 
> 


It would be good to see output of a ps -auxl next time he's running the 
test.

Eric