Re: [PATCH v6 2/5] cpufreq: powernv: Remove cpu_to_chip_id() from hot-path

[Balbir Singh]

On Fri, 22 Jan 2016 12:49:02 +0530
Shilpasri G Bhat <shilpa.bhat@xxxxxxxxxxxxxxxxxx> wrote:

> cpu_to_chip_id() does a DT walk through to find out the chip id by
> taking a contended device tree lock. This adds an unnecessary overhead
> in a hot path. So instead of calling cpu_to_chip_id() everytime cache
> the chip ids for all cores in the array 'core_to_chip_map' and use it
> in the hotpath.
> 
> Reported-by: Anton Blanchard <anton@xxxxxxxxx>
> Signed-off-by: Shilpasri G Bhat <shilpa.bhat@xxxxxxxxxxxxxxxxxx>
> Reviewed-by: Gautham R. Shenoy <ego@xxxxxxxxxxxxxxxxxx>

snip

Does the core_to_chip_map need to be updated/refreshed on/after/ a
cpu (core) hotplug? I presume id's don't change

Balbir