Re: Inconsistent IO performance
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On Sun, Aug 15, 2010 at 12:37:03PM -0700, Kevin Oberman wrote:
> OK. It's pretty clear that disk IO is terrible on this system. I suspect
> it's the SATA/PATA converter that is the throttle. In any case,
<snip>
> I still have no explanation for the variation. It's not vibration. Some
> of my best times were while the system was sitting in my trunk while
> commuting from my home to work. So have some of the worst.
If the performance is craptastic due to the SATA/PATA convertor, could that
also not be a good explanation for the variation? With the different speeds=
on
the two busses, there might well be variation between the time it takes for
commands to get through (altough one would expect that to even out over tim=
e).
Of course to test that you'd have to hook up a harddisk that doesn't need t=
he
convertor... If that improves the situation, you've found the problem.
> I can only hope that my next laptop, which should have ACHI, will improve
> the situation. I'll probably be getting a new laptop in the spring, so
> it won't be too long. Almost time to start trying to figure out what to
> buy.=20
Well, looking at my laptop's figures, it is possible to get good
throughput. If you get a system with ICH9 chipset (so you can use ahci(4)),
and a 7200 RPM harddisk, and you should be able to reproduce my figures, I
think.
Roland
--=20
R.F.Smith http://www.xs4all.nl/~rsmith/
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