David Dillow wrote:
On Thu, 2008-01-31 at 18:08 +0100, Bart Van Assche wrote:
If anyone has a suggestion for a better test than dd to compare the
performance of SCSI storage protocols, please let it know.
xdd on /dev/sda, sdb, etc. using -dio to do direct IO seems to work
decently, though it is hard (ie, impossible) to get a repeatable
sequence of IO when using higher queue depths, as it uses threads to
generate multiple requests.
This utility seems to be a good one, but it's basically the same as
disktest, although much more advanced.
You may also look at sgpdd_survey from Lustre's iokit, but I've not done
much with that -- it uses the sg devices to send lowlevel SCSI commands.
Yes, it might be worth to try. Since fundamentally it's the same as
O_DIRECT dd, but with a bit less overhead on the initiator side (hence
less initiator side latency), most likely it will show ever bigger
difference, than it is with dd.
I've been playing around with some benchmark code using libaio, but it's
not in generally usable shape.
xdd:
http://www.ioperformance.com/products.htm
Lustre IO Kit:
http://manual.lustre.org/manual/LustreManual16_HTML/DynamicHTML-20-1.html
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