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