Messages in this thread | | | Date | Mon, 7 Jan 2002 10:36:08 -0800 (PST) | From | Davide Libenzi <> | Subject | Re: 2.5.2-pre performance degradation on an old 486 |
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On Mon, 7 Jan 2002, Mikael Pettersson wrote:
> 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.
I'll post a patch to Linus in 20 minutes otherwise Linus simply
sched.c::init_idle()
current->dyn_prio = -100;
- Davide
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