Messages in this thread | | | From | Vincent Guittot <> | Date | Wed, 7 Jul 2021 12:50:15 +0200 | Subject | Re: [PATCH 1/3] sched/fair: Prepare variables for increased precision of EAS estimated energy |
| |
On Wed, 7 Jul 2021 at 12:41, Lukasz Luba <lukasz.luba@arm.com> wrote: > > > > On 7/7/21 11:32 AM, Vincent Guittot wrote: > > On Wed, 7 Jul 2021 at 12:29, Lukasz Luba <lukasz.luba@arm.com> wrote: > >> > >> > >> > >> On 7/7/21 11:11 AM, Vincent Guittot wrote: > >>> On Wed, 7 Jul 2021 at 12:06, Lukasz Luba <lukasz.luba@arm.com> wrote: > >>>> > >> > >> [snip] > >> > >>>> No. It's in 0.1uW scale, so 800Watts. Which is 16 CPUs * 64Watts > >>> > >>> Oh! you want 0.1uW precision .... This doesn't seem realistic at all. > >>> I'm not even sure that the power model can even reach an accuracy of > >>> 1mW > >>> > >> > >> True, the EM is registering platform with 1mW precision, but 1uW > > > > Do you mean 1uW or 0.1uW ? > > In this patch set I've proposed 0.1uW, but I'm open to drop one > order of magnitude. The 1uW still be good.
I don't want to underestimate the capabilities of the power model but I don't see which benefit you will get with 0.1uW precision With a 1uW precision the long type currently used for the returned value is fine for 32bits machine AFAICT
| |