From: Mikael Pettersson <mikpe@csd.uu.se>
To: torvalds@transmeta.com
Cc: axboe@suse.de, davidel@xmailserver.org,
linux-kernel@vger.kernel.org, mjh@vr-web.de
Subject: Re: 2.5.2-pre performance degradation on an old 486
Date: Mon, 7 Jan 2002 19:01:15 +0100 (MET) [thread overview]
Message-ID: <200201071801.TAA11871@harpo.it.uu.se> (raw)
On Mon, 7 Jan 2002 08:43:04 -0800 (PST), Linus Torvalds wrote:
>Hey, that would do it. It looks like the idle task ends up being a
>_normal_ process (just nice'd down), so it will get real CPU time instead
>of only getting scheduled when nothing else is runnable.
>
>Davide, I think the bounce-buffer is a red herring, it's simply that we're
>wasting time in idle..
This does seem to be the case. As a quick hack I added
if (p == &init_task) return -50;
at the start of kernel/sched.c:goodness() [to approximate the old
scheduler's behaviour], and this immediately restored performance
on my 486 to the old scheduler's levels.
/Mikael
next reply other threads:[~2002-01-07 18:01 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-07 18:01 Mikael Pettersson [this message]
2002-01-07 18:36 ` Davide Libenzi
-- strict thread matches above, loose matches on Subject: below --
2002-01-05 0:51 Mikael Pettersson
2002-01-05 8:25 ` Matthias Hanisch
2002-01-05 23:10 ` Davide Libenzi
2002-01-06 10:21 ` Jens Axboe
2002-01-06 10:33 ` Andre Hedrick
2002-01-07 7:22 ` Matthias Hanisch
2002-01-07 16:43 ` Linus Torvalds
2002-01-07 18:31 ` Davide Libenzi
2002-01-07 21:43 ` Matthias Hanisch
2002-01-07 22:17 ` Davide Libenzi
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