Re: [Eas-dev] [PATCH V3 2/3] cpufreq: schedutil: Process remote callback for shared policies

[Peter Zijlstra]

On Thu, Jul 13, 2017 at 07:02:37PM -0700, Saravana Kannan wrote:
> In all Qualcomm chipsets (well, at least the ones that have been used in
> Android devices so far), we can switch the frequency of any CPU from any
> other CPU. If we can do that even without fast switching, why wouldn't any
> theoretical fast switching be incapable of supporting this? Is this a
> limitation specific to x86 that we are assuming all architectures and
> platforms are going to have?

So the typical implementation of fast switching we're thinking of is the
CPU writing the DVFS request into a machine register. Now machine
registers are typically per logical CPU.

What style of fast switching were you thinking of?