Re: SATA drive performance seems low
Dne, 12. 12. 2009 07:14:28 je Stan Hoeppner napisal(a):
>
> I guess my first question is, why is the performance going through
> the
> Linux system cache buffers ~40% lower than doing a --direct read?
> Going
> through the Linux buffers is normal system operation. Second
> question
> is how do I improve buffered performance? Third, why is the sata_sil
> driver defaulting to UDMA/100 instead of UDMA/133, even after
> identifying the capability of the drive as UDMA/133?
I would think UDMA/100 is the upper limit of your SATA controller, so
your actual drive gets limited to UDMA5, although it's capable of
UDMA6:
> UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5 udma6
> Does this
> matter?
Yes, it does matter. And is probably at least *one* of the answers to
your first two questions.
> Is this slowing things down? Last question is, is the
> kernel/controller/drive already running at optimal performance, and
> I'm
> misreading reality?
It's most definitely slowing things down. Of course, I may be
misreading reality, as you aptly put it ;)
--
Regards,
Klistvud
Certifiable Loonix User #481801
http://bufferoverflow.tiddlyspot.com
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