Re: Pluggable Schedulers (was: [ANNOUNCE] RSDL completely fair starvation free interactive cpu scheduler)

From: Ryan Hope
Date: Fri Mar 09 2007 - 17:18:54 EST


from what I understood, there is a performance loss in plugsched
schedulers because they have to share code....

even if pluggable schedulers is not a viable option, being able to
choose which one was built into the kernel would be easy (only takes a
few ifdefs), i too think competition would be good

On 3/9/07, Al Boldi <a1426z@xxxxxxxxx> wrote:
William Lee Irwin III wrote:
> William Lee Irwin III wrote:
> >> I consider policy issues to be hopeless political quagmires and
> >> therefore stick to mechanism. So even though I may have started the
> >> code in question, I have little or nothing to say about that sort of
> >> use for it.
> >> There's my longwinded excuse for having originated that tidbit of code.
>
> On Fri, Mar 09, 2007 at 04:25:55PM +0300, Al Boldi wrote:
> > I've no idea what both of you are talking about.
>
> The short translation of my message for you is "Linus, please don't
> LART me too hard."

Right.

> On Fri, Mar 09, 2007 at 04:25:55PM +0300, Al Boldi wrote:
> > How can giving people the freedom of choice be in any way
> > counter-productive?
>
> This sort of concern is too subjective for me to have an opinion on it.

How diplomatic.

> My preferred sphere of operation is the Manichean domain of faster vs.
> slower, functionality vs. non-functionality, and the like. For me, such
> design concerns are like the need for a kernel to format pagetables so
> the x86 MMU decodes what was intended, or for a compiler to emit valid
> assembly instructions, or for a programmer to write C the compiler
> won't reject with parse errors.

Sure, but I think, even from a technical point of view, competition is a good
thing to have. Pluggable schedulers give us this kind of competition, that
forces each scheduler to refine or become obsolete. Think evolution.

> If Linus, akpm, et al object to the
> design, then invalid output was produced. Please refer to Linus, akpm,
> et al for these sorts of design concerns.

Point taken.

Linus Torvalds wrote:
> And hey, you can try to prove me wrong. Code talks. So far, nobody has
> really ever come close.
>
> So go and code it up, and show the end result. So far, nobody who actually
> *does* CPU schedulers have really wanted to do it, because they all want
> to muck around with their own private versions of the data structures.

What about PlugSched?


Thanks!

--
Al

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