kernel IO schedulers

[Kurt Wall]

On Thu, Dec 30, 2004 at 06:58:34AM -0800, Net Llama! took 31 lines to write:
> I could be wrong, but I think that in 2.6.10 there's a choice of several 
> different schedulers in the kernel:
> 
> # IO Schedulers
> #
> CONFIG_IOSCHED_NOOP=y
> CONFIG_IOSCHED_AS=y
> CONFIG_IOSCHED_DEADLINE=y
> CONFIG_IOSCHED_CFQ=y
> 
> What I'm wondering is what happens if you chose Y for all of them (as 
> above)?

Did you modify the scheduler with a command line argument, such as
"eleveator=deadline"? You can replace "deadline" with "as" or "noop".
There are also some tunables, but it eludes me right now where I read
about them.

> The reason I'm asking is that I did choose Y for all of them, and now in 
> 2.6.10 (but not in earlier kernels) i'm getting some horrific 
> performance in X (XFCE specifically).  Scrolling in windows is sluggish, 
> sometimes even typing gets lagged.  I'm starting to think that I was 
> supposed to choose just one of the schedulers, but I'd like some input.

I have the same config (but on 2.6.9) and haven't noticed any grievous
performance issues.

Kurt
-- 
Steinbach's Guideline for Systems Programming:
	Never test for an error condition you don't know how to
handle.