Re: [patch] O(1) scheduler, -D1, 2.5.2-pre9, 2.4.17

Ingo Molnar
2002-01-07T19:39:29Z

On Mon, 7 Jan 2002, Linus Torvalds wrote:

> Ingo, looks true. A quick -D2?

yep, Brian is right. I've uploaded -D2:

http://redhat.com/~mingo/O(1)-scheduler/sched-O1-2.5.2-D2.patch

other changes:

- make rt_priority 99 map to p->prio 0, rt_priority 0 map to p->prio 99.

- display 'top' priorities correctly, 0-39 for normal processes, negative
values for RT tasks. (it works just fine it appears.) We did not use to
display the real priority of RT tasks, but now it's natural.

> Oh, and please move console_init() back, other consoles (sparc?) may
> depend on having PCI layers initialized.

(doh, done too, fix is in -D2.)

> Oh, and _I_ don't like "cpu()". What's wrong with the already
> existing "smp_processor_id()"?

nothing serious, my main problem with it is that it's often too long for
my 80 chars wide consoles, and it's also too long to type and i use it
quite often in SMP code.

IIRC we had a 'hard_smp_processor_id()' initially, partly to make it
harder to use it. (it was very slow because it did an APIC read). But
these days smp_processor_id() is just as fast (or even faster) as
'current'. So i wanted to use cpu() in new code to make it easier to read
and to make it more compact. But if this is a problem i can remove it.
I've verified that there is no obvious namespace collisions.

(i've done a quick UP sanity compile + boot of 2.5.2-pre9 + D2, it all
works as expected.)

Ingo