ULE nice behavior fixed.

[Jeff Roberson]

On Wed, 2 Apr 2003, Bruce Evans wrote:

> On Wed, 2 Apr 2003, Sheldon Hearn wrote:
>
> > On (2003/04/02 01:54), Jeff Roberson wrote:
> >
> > > It probably still needs some tweaking but it seems to be MUCH better now.
> > > New algorithm entirely.
> > >
> > > nice +20 processes will not run if anything else wants to.
> >
> > Some of us have been waiting for that behaviour for a long time (long
> > before you started working on ULE).
>
> Er, this is the normal behaviour in FreeBSD-3.0 through FreeBSD-4.8,
> so you shouldn't have waited more than negative 4 years for it :-).
> The strict implementation of this behaviour in these releases causes
> priority inversion problems, but the problems apparently aren't very
> important.  The scaling of niceness was re-broken in -current about 3
> years ago to "fix" the priority inversion problems.  This is with
> SCHED_4BSD.  SCHED_ULE has larger problems.
>

Do you know of any problem other than idlepri breakage?  I just fixed
that.  I'm about to get on a plane so I don't have time to benchmark it.
If you have a chance I'd love to see how the most recent fixes effect your
buildworld time.

I still have to microoptimize the code a bit to get rid of switch
statements etc, but it all works.

Cheers,
Jeff