Re: [patch] cfq: ioprio inherit rt class

[Horst von Brand <vonbrand@inf.utfsm.cl>]

Lee Revell <rlrevell@joe-job.com> wrote:
> On Sat, 2006-06-03 at 10:10 +1000, Con Kolivas wrote:
> > On Saturday 03 June 2006 03:12, Jens Axboe wrote:
> > > Not sure. RT io needs to be considered carefully, but I guess so does RT
> > > CPU scheduling. For now I'd prefer to play it a little safer, and only
> > > inheric the priority value and not the class.

> > The problem I envisioned with that was that realtime tasks, if they
> > don't specify an io priority (as most current code doesn't), would
> > basically get io priority 4 and have the same proportion as any nice 0
> > SCHED_NORMAL task whereas -nice tasks automatically are getting better
> > io priority. How about givent them normal class but best priority so
> > they are at least getting the same as nice -20?

> Have you seen RT threads trying to disk IO 'in the wild'

I'd be surprised, to be sure.

>                                                          or is this a
> theoretical concern?  I don't know of any such apps.

Is it hard to do? If not, as this isn't forbidden as such, it makes sense
IMVHO.
-- 
Dr. Horst H. von Brand                   User #22616 counter.li.org
Departamento de Informatica                     Fono: +56 32 654431
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