On Tue, Jan 16, 2007 at 08:29:10AM +0000, Andrew Doran wrote:
> 
> > 1. What to do about priority range? It is currently fixed to
> >    0..127. Different scheduler implementations may want to use a
> >    different priority range. But I'm not sure if allowing a variable
> >    priority range is really sane. All other systems have a fixed range
> >    (FreeBSD has 255, Solaris has 169, Linux has 139), IIRC.
> > 
> >    Personally, I'd vote to increase MAXPRI at least to 159, which
> >    should be fairly enough for any scheduler.
> 
> I'm stating the obvious, but I think the main considerations are keeping
> traversal of the queues cheap, while still providing decent granularity.

I agree.  The current scheduler only has 32 actual priorities - even though
some of the calculations are done to a larger precision.  That is probably
more than enough for non-fixed priorities.  After all the 'priority' value
of a non-running process is irrelevant, priorities only matter when there
is more than one runnable process....

	David

-- 
David Laight: david@l8s.co.uk