Re: RSDL v0.31

From: Ingo Molnar
Date: Sat Mar 17 2007 - 03:56:57 EST



* Nicholas Miell <nmiell@xxxxxxxxxxx> wrote:

> > I'm saying that the current scheduler adjusts for interactive loads,
> > this new one doesn't. I'm seeing interactivity regressions, and
> > they are not fixed with nice unless nice is used to maximum effect.
> > I'm saying yes, I can lower my expectations, but no I don't want to.
>
> Uh, no. Essentially, the current scheduler works around X's
> brokenness, in an often unpredictable manner.

No. The two schedulers simply use different heuristics. RSDL uses _less_
heuristics, and thus gets some workloads right that the heuristics in
the current scheduler got wrong. But it also gets some other workloads
wrong.

so basically, the current scheduler has a built-in "auto-nice" feature,
while RSDL relies more on manual assignment of nice values.

if you want no heuristics at all you can do it in the current scheduler:
use SCHED_BATCH on your shell and start up X with that. I'd not mind
tweaking SCHED_BATCH with an RSDL-alike timeslice quota system.

so it is not at all clear to me that RSDL is indeed an improvement, if
it does not have comparable auto-nice properties.

Ingo
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