Jon Nelson wrote:
On Wed, 4 Apr 2007, Bill Anderson wrote:
I noticed that the default elevator applies to everything, including USB
memory sticks. I thought the block device driver would change the I/O
scheduler to something more appropriate for a memory stick, such as the noop
scheduler. I switched to the noop scheduler for just the memory stick, and
there was an improvement in performance. I haven't done a detailed statistical
analysis to verify my empirical impression.
I have a few questions:
1) Is there a reason for the block device driver not changing the I/O
scheduler to noop?
2) How do I modify HAL to change the I/O scheduler when it detects that a
hotplug for a memory stick?
I can't answer (1), and (2) is probably pretty easy.
However, let me offer an alternative:
set the *default* I/O scheduler (there /are/ several schedulers, you
know) to noop and then at boot time re-set your HDD (or whatever local
devices you want to change back) to "anticipatory" (or whatever you
use).
--
Carpe diem - Seize the day.
Carp in denim - There's a fish in my pants!
Jon Nelson <[EMAIL PROTECTED]>
Setting elevator=<somevalue> as boot command changes the default
scheduler. It would really slow down the disk until it reached the
boot.local script. Under Suse 10.2 and FC6, the kernel default scheduler
is CFQ. I still want CFQ for the USB DVD drive, or a thumb drive. Thus,
I am looking for a way for to configure HAL to change the elevator from
cfq to noop upon detection of the memory stick.
Bill Anderson
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