Re: [patch] O(1) scheduler-H6/H7/I0 and nice +19

[Robert Love]

On Tue, 2002-01-15 at 21:04, Davide Libenzi wrote:

> On 15 Jan 2002, Robert Love wrote:
> > This isn't a bad idea, as long as we don't use it as a crutch or
> > excuse.  That is, answer scheduling problems with "properly nice your
> > tasks" -- the scheduler should be smart enough, to some degree.
> >
> > FWIW, Solaris actually implements a completely different scheduling
> > policy, SCHED_INTERACT or something.  It is for windowed tasks in X --
> > they get a large interactivity bonus.

> Now ( with 2.5.3-pre1 ) intractivity is *very good* but SCHED_INTERACT
> would help *a lot* to get things even more right.

I looked it up; its called class IA.  I don't know if it grows from a
limitation of their scheduler (i.e. they can't calculate priority and be
as fair to interactive tasks as us) or if it offers a fundamental
advantage.  I suspect their are a myriad of things things we can do with
an interactive/GUI scheduling policy.

One thing this is, since their kernel is preemptible, it marks processes
that very much always deserve a scheduling boost based on interactivity,
and thus their interactivity is quite nice.

	Robert Love