Re: [2.4.17/18pre] VM and swap - it's really unusable

[george anzinger]

Daniel Phillips wrote:
> 
> On January 14, 2002 10:09 am, [e-mail] wrote:
> > UNIX generally tries to ensure liveness. So you know that
> >       cat lkarchive | grep feel | wc
> > will complete and not just that, it will run pretty reasonably because
> > for UNIX _every_ process is important and gets cpu and IO time.
> > When you start trying to add special low latency tasks, you endanger
> > liveness.  And preempt is especially corrosive because one of the
> > mechanisms UNIX uses to assure liveness is to make sure that once a
> > process starts it can do a significant chunk of work.
> 
If I read this right, your complaint is not with preemption but with
scheduler policy.  Clearly both are needed to "assure liveness". 
Another way of looking at preemption is that is enables a more
responsive and nimble scheduler policy (afterall it is the scheduler
that decided that task A should give way to task B.  All preemption does
is to allow that to happen with greater dispatch.)  Given that, we can
then discuss what scheduler policy should be.
-- 
George           [e-mail]
High-res-timers: http://sourceforge.net/projects/high-res-timers/
Real time sched: http://sourceforge.net/projects/rtsched/