ULE nice behavior fixed.

[Bruce Evans]

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.

Bruce