Re: [RFD PATCH 3/5] sched/cpufreq_schedutil: make worker kthread be SCHED_DEADLINE

From: Rafael J. Wysocki
Date: Thu Mar 30 2017 - 16:28:21 EST


On Thursday, March 30, 2017 08:50:11 AM Vikram Mulukutla wrote:
>
> > OK
> >
> > So there are two pieces here.
> >
> > One is that if we want *all* drivers to work with schedutil, we need to
> > keep
> > the kthread for the ones that will never be reworked (because nobody
> > cares
> > etc). But then perhaps the kthread implementation may be left alone
> > (because
> > nobody cares etc).
> >
> > The second one is that there are drivers operating in-context that work
> > with
> > schedutil already, so I don't see major obstacles to making more
> > drivers work
> > that way. That would be only a matter of reworking the drivers in
> > question.
> >
> > Thanks,
> > Rafael
>
> There are some MSM platforms that do need a kthread and would love to
> use
> schedutil. This is all mainly due to the point that Vincent raised;
> having
> to actually wait for voltage transitions before clock switches. I can't
> speak about the future, but that's the situation right now. Leaving the
> kthread alone for now would be appreciated!

I was not arguing for removing the kthread (quite opposite rather).

My point was that *if* it is viable to rework drivers to operate in-context,
that would be the way to go IMO instead of messing up with the kthread thing.

Thanks,
Rafael