Re: [PATCH v5 1/8] Documentation: arm: define DT cpu capacity-dmips-mhz bindings

From: Juri Lelli
Date: Wed Jun 15 2016 - 10:24:47 EST


On 15/06/16 14:51, Vincent Guittot wrote:
> On 15 June 2016 at 12:17, Juri Lelli <juri.lelli@xxxxxxx> wrote:

[...]

> > +==========================================
> > +ARM CPUs capacity bindings
> > +==========================================
> > +
> > +==========================================
> > +1 - Introduction
> > +==========================================
> > +
> > +ARM systems may be configured to have cpus with different power/performance
> > +characteristics within the same chip. In this case, additional information
> > +has to be made available to the kernel (the scheduler in particular) for
>
> not sure that it's worth mentioning the scheduler in particular here
>

OK. I can remove that bit.

> > +it to be aware of such differences and take decisions accordingly.
> > +

[...]

> > +==========================================
> > +3 - capacity-dmips-mhz
> > +==========================================
> > +
> > +capacity-dmips-mhz is an optional cpu node [1] property: u32 value
> > +representing CPU capacity expressed in normalized DMIPS/MHz. At boot time, the
> > +maximum frequency available to the cpu is then used to calculate the capacity
> > +value internally used by the kernel.
> > +
> > +capacity-dmips-mhz property is all-or-nothing: if it is specified for a cpu
> > +node, it has to be specified for every other cpu nodes, or the system will
> > +fall back to the default capacity value for every CPU. If cpufreq is not
> > +available, final capacities are calculated by directly using capacity-dmips-
> > +mhz values (normalized w.r.t. the highest value found while parsing the DT).
>
> looks good to me
>

Great! Thanks for reviewing this.

Best,

- Juri