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Date: Tue, 24 Apr 2007 08:08:56 -0700
From: "Ray Lee" <madrabbit@gmail.com>
Reply-To: ray-gmail@madrabbit.org
To: "Linus Torvalds" <torvalds@linux-foundation.org>
Subject: Re: [REPORT] cfs-v4 vs sd-0.44
Cc: "Ingo Molnar" <mingo@elte.hu>, "Nick Piggin" <npiggin@suse.de>,
       "Juliusz Chroboczek" <jch@pps.jussieu.fr>,
       "Con Kolivas" <kernel@kolivas.org>, "ck list" <ck@vds.kolivas.org>,
       "Bill Davidsen" <davidsen@tmr.com>, "Willy Tarreau" <w@1wt.eu>,
       "William Lee Irwin III" <wli@holomorphy.com>,
       linux-kernel@vger.kernel.org,
       "Andrew Morton" <akpm@linux-foundation.org>,
       "Mike Galbraith" <efault@gmx.de>,
       "Arjan van de Ven" <arjan@infradead.org>,
       "Peter Williams" <pwil3058@bigpond.net.au>,
       "Thomas Gleixner" <tglx@linutronix.de>, caglar@pardus.org.tr,
       "Gene Heskett" <gene.heskett@gmail.com>
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On 4/23/07, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Mon, 23 Apr 2007, Ingo Molnar wrote:
> >
> > The "give scheduler money" transaction can be both an "implicit
> > transaction" (for example when writing to UNIX domain sockets or
> > blocking on a pipe, etc.), or it could be an "explicit transaction":
> > sched_yield_to(). This latter i've already implemented for CFS, but it's
> > much less useful than the really significant implicit ones, the ones
> > which will help X.
>
> Yes. It would be wonderful to get it working automatically, so please say
> something about the implementation..
>
> The "perfect" situation would be that when somebody goes to sleep, any
> extra points it had could be given to whoever it woke up last. Note that
> for something like X, it means that the points are 100% ephemeral: it gets
> points when a client sends it a request, but it would *lose* the points
> again when it sends the reply!

It would seem like there should be a penalty associated with sending
those points as well, so that two processes communicating quickly with
each other won't get into a mutual love-fest that'll capture the
scheduler's attention.

Ray