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From: Robert Lipe <robertlipe@usa.net>
Subject: Re: Informix faster on UW7/OKP than native OS5 ? References: <bu38ad$ei4$1@newsread.albacom.net>
Date: Wed, 14 Jan 2004 09:52:08 -0600

On Wed, 14 Jan 2004 12:15:49 +0100, Roberto Zini <rob@robnothere.com> wrote:

> I performed some other non Informix related tests such as "openssl 
> speed" (OS5 outperformed - in some case - OKP by a factor of 2-3%) and a 
> "tar xvf" of a 80MB file, which again showed that OS5 was faster (20s vs 
> 1m04s).

UnixWare's 'tar' and UnixWare's default filesystem paramaters conspire
to deliver an, uuuuh, less than satisfying performance experience.
The rapid creation of files and the explict call to fsync is an
achilles heel.  Be sure your filesystems are being mounted without
'mincache=closesync' to help things along.   I also find GNU tar to be
about 30% faster on extraction than either of the System V tars shipped
with UnixWare.

> optimized filesystem performances, I was wondering if UnixWare7/OKP (out 
> of the box) can indeed be faster than OS5 while __READING__ and slower 
> while __WRITING__.

I know both systems reasonably well and I'm sure I can produce a test
showing either one faster depending on who is asking. :-) The results
you posted aren't really suprising to me.  I do suspect with only minor
tweaking, you can reduce or eliminate the write penalty.

On modernish, robust hardware, it doesn't suprise me that UnixWare +
one of the personality modules outperforms the OS being impersonated
in many (not all) cases.  If the environment being tested it totally
computationally bound in user space, I'd expect it to be a wash.  The
more time you spend using OS services like VM or I/O, the more you're
likely to gain, but there are specific services that will go either way.

The filesystem paramaters have a LOT to do with perceived performance,
esp in a case like your tar extraction test.  If you're spending your
life creating and writing what are essentially temporary files (as one
might be when, say, compiling software) it's worth noting that the UW
filesystem defaults may penalize you.

        http://uw713doc.sco.com/en/FS_admin/_Choosing_a_Mount_Mode.html
        http://uw713doc.sco.com/en/ODM_FSadmin/fssag-8.html

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