Tejun Heo wrote:
François-Julien Marbaud wrote:
Hi !
I'm doing an internship in a research lab, and we are trying to use a
P.ATA SSD
in order to speed-up a genome computation software.
We got a performance problem, expecially with access time : access
time is about
800us, and according to the manufacturer it should be about 40us. The
bandwith
is OK.
The SSD is a 2.5' flash hard drive, the slave of the first IDE channel.
We wonder if that could be the because P.ATA driver is not really done
for small
access times, so we got such a poor time. In that case, I guess we
would have to
have a closer look at the driver ...
First of all, try noop elevator.
echo noop > /sys/block/hdx/queue/scheduler
Depending on your workload, adjusting plugging delay/threshold
parameters might help. These are initialized in the kernel source file
block/ll_rw_blk.c::blk_queue_make_request(). q->unplug_thresh and
q->unplug_delay.
And one more thing, if a 67MB~4GB SDD drive speeds up the computation,
something is wrong. 4GB main memory will be much better than 4GB SDD
for such purposes.
--
tejun
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