Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!samsung!spool.mu.edu!uunet!bcstec!misty!jsadler
From: jsadler@misty.boeing.com (Jim Sadler)
Newsgroups: comp.benchmarks
Subject: Re: Measuring disk read times for Unix
Message-ID: <23410002@misty.boeing.com>
Date: 28 Feb 91 04:50:55 GMT
References: <714@opus.NMSU.Edu>
Organization: Boeing Commercial Airplane BCS Support
Lines: 27

>/ misty:comp.benchmarks / taylor@intellistor.com (Dick Taylor) /  3:30 pm  Feb 27, 1991 /
>In article <714@opus.NMSU.Edu> pfeiffer@nmsu.edu (Joe Pfeiffer) writes:
>>...
>>In order to measure write times, I'm using the O_SYNC to flush my data
>>to disk on each write.  So far so good.
>>
>>I'm having trouble trying to do the equivalent for reads.  I appear to
	.
	.
	.
>
>There are a number of ways to do it.  The niftiest that I ever found was
>to use the mount() and unmount() system calls to unmount the filesystem
>between each iteration of the benchmark.  One warning, though -- this
	.
	.
	.
>			-- Dick Taylor
>			   Intellistor, Inc.
Would it possible to regen the kernel with the buffer set to the lowest
value, for the purpose of this type of test ?  Then you wouldn't have to
pass as much data though to clean out the buffer or have the unwanted
overhead as the mount(), unmount() way.  Of course if the overhead of
cleaning out the buffer is the same or greater than un/mount() it's not
such a great idea.

jim