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Date:      Sat, 8 Apr 1995 09:19:53 -0700 (PDT)
From:      "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com>
To:        taob@gate.sinica.edu.tw (Brian Tao)
Cc:        freebsd-current@FreeBSD.org
Subject:   Re: Disk performance
Message-ID:  <199504081619.JAA15432@gndrsh.aac.dev.com>
In-Reply-To: <Pine.BSI.3.91.950408214953.787U-100000@aries.ibms.sinica.edu.tw> from "Brian Tao" at Apr 8, 95 09:51:56 pm

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> 
> On Sat, 8 Apr 1995, Gary Jennejohn wrote:
> > 
> > 1st level cache: 407 MB/sec
> [...]
> > 1st level cache: 391 MB/sec
> 
>     Why would taking out the L2 cache slow down data transfer to and
> from the primary cache?

I attribute the above difference to an insignificant accuracy in
the test results.  (407-391)/391 = 4%, I suspect repeated runs of
the same test on the same exact machine probably have a 5% variance
in values.  I see similiar variances with the program I use,
from 227 to 263MB/sec or about 16% variation.

-- 
Rod Grimes                                      rgrimes@gndrsh.aac.dev.com
Accurate Automation Company                   Custom computers for FreeBSD



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