Re: 2.5.2-pre performance degradation on an old 486

[Davide Libenzi]

On Mon, 7 Jan 2002, Matthias Hanisch wrote:

> On Mon, 7 Jan 2002, Davide Libenzi wrote:
>
> > In sched.c::init_idle() :
> >
> > current->dyn_prio = -100;
> >
> > Let me know.
>
> Aehm. I already added the same line at the beginning of cpu_idle() in
> arch/i386/process.c, which brought back the old performance. Your patch
> should be analogous, but cleaner.
>
> So: Bingo!!!!
>
> I just wonder, why only two people with slow machines saw this behavior...
>
> Now 2.5.2 can come :)

The problem is that slow machines shows different dyn_prio distribution.
What happened was that if a process with dyn_prio == was wake up while the
idle was running, preemption_goodness() failed to kick out the idle ( with
dyn_prio == 0 ) because of the strict > 0

- Davide