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From: se@zpr.uni-koeln.de (Stefan Esser)
Date: Thu, 9 Nov 1995 00:30:51 +0100
In-Reply-To: faulkner@mpd.tandem.com (Boyd Faulkner)
       "iozone and mount -o async" (Nov  8, 16:12)
X-Mailer: Mail User's Shell (7.2.6 alpha(2) 7/9/95)
To: faulkner@mpd.tandem.com (Boyd Faulkner)
Subject: Re: iozone and mount -o async
Cc: current@freebsd.org
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On Nov 8, 16:12, Boyd Faulkner wrote:
} Subject: iozone and mount -o async

} With my Maxtor 235M SCSI 1 drive mounted normally
} 
} iozone 32 gives

} IOZONE performance measurements:
}         804903 bytes/second for writing the file
}         1112974 bytes/second for reading the file
} 
} mounted with -o async

} IOZONE performance measurements:
}         714042 bytes/second for writing the file
}         1115575 bytes/second for reading the file

I'm seeing slower writes, too, and surprisingly 
by about the same absolute amount (some 100KB/s).

My "iozone 32" results are:

se@x14> tail -3 /tmp/sync.io 
IOZONE performance measurements:
        2529427 bytes/second for writing the file
        4446135 bytes/second for reading the file
se@x14> tail -3 /tmp/async.io 
IOZONE performance measurements:
        2422429 bytes/second for writing the file
        4423241 bytes/second for reading the file


Bonnie gives significantly different results, too:

              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
sync      100  1505 98.6  3267 31.2  2167 42.3  1656 98.5  5929 72.1  78.4  9.2
async     100  1425 96.4  2661 24.3  2077 41.7  1644 98.0  5923 72.1  78.9  9.1


All tests on the half ful inner (slower) half of my 
2GB Atlas driven by an ASUS SP3G, 486DX2/66, NCR SCSI.


Regards, STefan

-- 
 Stefan Esser, Zentrum fuer Paralleles Rechnen		Tel:	+49 221 4706021
 Universitaet zu Koeln, Weyertal 80, 50931 Koeln	FAX:	+49 221 4705160
 ==============================================================================
 http://www.zpr.uni-koeln.de/~se			  <se@ZPR.Uni-Koeln.DE>