Re: anticipatory scheduling questions

From: Andrew Morton (akpm@digeo.com)
Date: Fri Feb 28 2003 - 18:16:24 EST


"Felipe Alfaro Solana" <felipe_alfaro@linuxmail.org> wrote:
>
> ----- Original Message -----
> From: Andrew Morton <akpm@digeo.com>
> Date: Fri, 28 Feb 2003 11:14:18 -0800
> To: "Felipe Alfaro Solana" <felipe_alfaro@linuxmail.org>
> Subject: Re: anticipatory scheduling questions
>
> > "Felipe Alfaro Solana" <felipe_alfaro@linuxmail.org> wrote:
> > > I have done so: Evolution is a complex application with many interdependencies and is
> > > not very prone to launch diagnostic messages to the console. Anyways, I haven't seen
> > > any diagnostic message in the console. I still think there is something in the AS I/O scheduler
> > > that is not working at full read throughput. Of course I'm no expert.
> >
> > It certainly does appear that way. But you observed the same runtime
> > with the deadline scheduler. Or was that a typo?
> >
> > > > 2.4.20-2.54 -> 9s
> > > > 2.5.63-mm1 w/Deadline -> 34s
> > > > 2.5.63-mm1 w/AS -> 33s
>
> It wasn't a typo... In fact, both deadline and AS give roughly the same
> timings (one second up or down). But I
> still don't understand why 2.5 is performing so much worse than 2.4.

Me either. It's a bug.

Does basic 2.5.63 do the same thing? Do you have a feel for when it started
happening?

> Could a "vmstat" or "iostat" dump be interesting?

2.4 versus 2.5 would be interesting, yes.

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