[PATCH] cpuidle/pseries: Fixup CEDE0 latency only for POWER10 onwards

[Michal Suchánek]

On Thu, Apr 22, 2021 at 08:37:29PM +0530, Gautham R. Shenoy wrote:
> From: "Gautham R. Shenoy" <ego at linux.vnet.ibm.com>
> 
> Commit d947fb4c965c ("cpuidle: pseries: Fixup exit latency for
> CEDE(0)") sets the exit latency of CEDE(0) based on the latency values
> of the Extended CEDE states advertised by the platform
> 
> On some of the POWER9 LPARs, the older firmwares advertise a very low
> value of 2us for CEDE1 exit latency on a Dedicated LPAR. However the
Can you be more specific about 'older firmwares'?

Also while this is a performance regression on such firmwares it
should be fixed by updating the firmware to current version.

Having sub-optimal performance on obsolete firmware should not require a
kernel workaround, should it?

It's not like the kernel would crash on the affected firmware.

Thanks

Michal