Re: [PATCH] cpufreq: 1/4 SMT awareness: save cpumask_t cpus

[Dominik Brodowski <linux@dominikbrodowski.de>]

On Fri, Aug 20, 2004 at 01:35:10AM -0400, Zwane Mwaikambo wrote:
> Hi Venkatesh,
> 
> On Wed, 18 Aug 2004, Pallipadi, Venkatesh wrote:
> 
> > 2) Or leave the synchronization overhead to the policy governor.
> > Driver only says a set of CPUs will be affected by the change.
> > It is the responsibility of the governor to take care of
> > SMT synchronization and preventing one CPU slowing down all
> > the other ones. Governor should only write only when all dependent
> > CPUs are idle.
> >
> > I think Dominik is thinking of option 2.
> > I see advantages in option 2 as governor can do the synchronization
> > at one place, instead of that being done in each low level driver.
> > But, having said that, with option 2, a dumb governor may not do
> > proper synchronization at all.
> 
> Indeed, it 2 would make the most sense especially since we have the
> topology information. I'll generate and test a patch as soon as i can.

Actually, I do favor "2" by large, and there simply may not be "dumb"
governors once we propagate the SMT awareness to the cpufreq core. Zwane,
are you aware of my current patch set which aims at the same direction? IIRC
[and my memory might be a bit off after a long vacation], it mostly needs
work from the "governor" perspective -- and testing. Don't have hardware
here...

Thanks,
	Dominik