Re: [patch] voluntary-preempt-2.6.9-rc3-mm3-T3

From: Lee Revell
Date: Fri Oct 08 2004 - 13:33:47 EST


On Fri, 2004-10-08 at 02:49, Con Kolivas wrote:
> Lee Revell wrote:
> > On Thu, 2004-10-07 at 19:26, Rui Nuno Capela wrote:
> >
> >>Ingo Molnar wrote:
> >>
> >>>>i've released the -T3 VP patch:
> >>>> http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.9-rc3-mm3-T3
> >>>>
> >>>
> >>OK. Just to let you know, both of my personal machines are now running on
> >>bleeding-edge 2.6.9-rc3-mm3-T3, and very happily may I assure :)
> >
> >
> > This actually feels a _lot_ snappier than mm2, which seemed prone to
> > weird stalls. I don't have any numbers to back this up yet.
>
> mm2 had a completely different cpu scheduler so no meaningful comparison
> can be made. Try comparing to mm3 vanilla.

Well, I figured the change from -mm2 to -mm3 was responsible, as I have
never seen the VP patches make a perceptible difference in system
response time. The VP effect only becomes apparent when you do
something that really needs millisecond or sub-ms latency. I guess a
bug in the VP patch could cause performance regressions though. However
no one reported sluggishness with mm2+S7, but it's apparent when you try
mm3+T3 that it feels a lot more responsive.

Anyway I was just wondering if there was an obvious change that would
cause this.

Lee

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