Re: [PATCH] Staircase Scheduler v6.3 for 2.6.7-rc2

Felipe Alfaro Solana
2004-06-29T12:05:45Z

On Tue, 2004-06-29 at 13:10 +0200, Pavel Machek wrote:
> Hi!
>
> > This is an update of the scheduler policy mechanism rewrite using the
> > infrastructure of the current O(1) scheduler. Slight changes from the
> > original design require a detailed description. The change to the original
> > design has enabled all known corner cases to be abolished and cpu
> > distribution to be much better maintained. It has proven to be stable in my
> > testing and is ready for more widespread public testing now.
> >
> >
> > Aims:
> > - Interactive by design rather than have interactivity bolted on.
> > - Good scalability.
> > - Simple predictable design.
> > - Maintain appropriate cpu distribution and fairness.
> > - Low scheduling latency for normal policy tasks.
> > - Low overhead.
> > - Making renicing processes actually matter for CPU distribution (nice 0 gets
> > 20 times what nice +20 gets)
> > - Resistant to priority inversion
>
> How do you solve priority inversion?
>
> Can you do "true idle threads" now? (I.e. nice +infinity?)

I think idle threads can be achieved with the batch scheduler policy
present in -ck patches. It works nicely, and I use it a lot.

PS: At least, if you mean with "idle threads" those that do only run
where there are idle cycles of CPU (i.e. all processes are sleeping).