I/O Scheduling results in poor responsiveness

[Chris Snook]

Bruno Wolff III wrote:
> On Wed, Mar 05, 2008 at 14:35:41 -0500,
>   Chris Snook <csnook at redhat.com> wrote:
>> Ultimately, if latency is a high priority for you, you should switch to the 
>> deadline scheduler.
> 
> Is there an easy way to do this? My desktop seems pretty sluggish since
> switching to rawhide and I suspect it is disk IO related. I'd like to
> try out another scheduler and see if it helps.

At the grub screen, hit 'a' to append kernel arguments, and add 
elevator=deadline to the list of parameters.  If you like the results, 
you can add it permanently by editing /boot/grub/grub.conf.

It's also possible that your sluggish rawhide performance is due to all 
the extra debug options that are turned on in the rawhide kernel.  I've 
seen overhead as high as 30% on some workloads.  There's been some 
discussion of adding a 'nodebug' kernel variant to rawhide that's 
compiled with roughly the same options as the stable Fedora kernel, but 
I don't know when or if that's going to happen.

	-- Chris