Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!edi386!eddjp
From: eddjp@edi386.UUCP ( Dewey Paciaffi )
Newsgroups: comp.benchmarks
Subject: Re: Sparcstation 2 Write I/O
Message-ID: <159@edi386.UUCP>
Date: 20 Feb 91 22:18:38 GMT
References: <1991Feb16.145828.12539@maths.tcd.ie> <155@edi386.UUCP> <1991Feb19.101559.8441@maths.tcd.ie>
Reply-To: eddjp@edi386.UUCP ( Dewey Paciaffi )
Organization: J.M. Huber Corp., Edison,NJ
Lines: 56

In article <1991Feb19.101559.8441@maths.tcd.ie> ajudge@maths.tcd.ie (Alan Judge) writes:
>In <155@edi386.UUCP> eddjp@edi386.UUCP ( Dewey Paciaffi ) writes:
>>I've also gotten similar results  dd and mkfile. Unfortunately all of my
>
>The main difference, I think, is not write vs dd, but the size of the
>buffer used.

After having received several suggestions to increase the buffer size
on the write test I was running on the Sparc2, I did just that. Here's
the results along with those for a RS/6000 Model 320.

==============================================================================

          SunOs 4.1.1 Write System call, 10 MB file

     Buffer Size      Avg time in Seconds      KB / Second
     -----------      -------------------      -----------

        1024                37.55                 272.7
        2048                37.43                 273.6
        4096                37.05                 276.4
        8192                 8.36                1224.9  * Note change
       16384                 8.36                1224.9
       32768                 8.43                1214.7
       65536                 8.71                1175.7



            AIX 3.1 Write System call, 10 MB file

     Buffer Size      Avg time in Seconds      KB / Second
     -----------      -------------------      -----------

        1024                 5.57                1838.5
        2048                 6.62                1546.8
        4096                 6.20                1648.9
        8192                 6.21                1648.9 
       16384                 5.35                1914.4
       32768                 5.35                1914.0
       32768                 9.18                1115.5

==============================================================================

The tests were run 6 times at each buffer size and averaged. The Sparc2
tests were run on an external 669 MB drive, and similar results
were obtained on a second Sparc2, using its internal drive. The RS/6000
tests were run on an internal 320 IBM drive.

The remarkable change in throughput on the Sparc at 8k buffers surprised me a
little. Apparently the Standard I/O package takes this into account though,
because a 10 MB file written out in 1024 blocks with fputs returns in
about 8.5 seconds.

Other than that, the RS/6000 just looks a little faster...
-- 
Dewey Paciaffi           ...!uunet!edi386!eddjp


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