Re: 2.5.2-pre performance degradation on an old 486

[Davide Libenzi]

On Mon, 7 Jan 2002, Matthias Hanisch wrote:

> On Sat, 5 Jan 2002, Davide Libenzi wrote:
>
> > There should be some part of the kernel that assume a certain scheduler
> > behavior. There was a guy that reported a bad  hdparm  performance and i
> > tried it. By running  hdparm -t  my system has a context switch of 20-30
> > and an irq load of about 100-110.
>
> This guy was me, IMHO (just with my office email address :).
>
>
> > The scheduler itself, even if you code it in visual basic, cannot make
> > this with such loads.
> > Did you try to profile the kernel ?
>
> To answer your question, I wanted to profile 2.5.2-pre8 against
> 2.5.2-pre8-old-scheduler. _Fortunately_ I made some mistake and forgot to
> back out the following chunk of memory.
>
> --- v2.5.1/linux/arch/i386/kernel/process.c     Thu Oct  4 18:42:54 2001
> +++ linux/arch/i386/kernel/process.c    Thu Dec 27 08:21:28 2001
> @@ -125,7 +125,6 @@
>         /* endless idle loop with no priority at all */
>         init_idle();
>         current->nice = 20;
> -       current->counter = -100;

In sched.c::init_idle() :

current->dyn_prio = -100;

Let me know.

- Davide