Re: [PATCH v4 1/2] powerpc/time: Only set CONFIG_ARCH_HAS_SCALED_CPUTIME on PPC64

[Nicholas Piggin]

Christophe Leroy's on August 14, 2019 4:31 pm:
> Hi Nick,
> 
> 
> Le 07/06/2018 Ã 03:43, Nicholas Piggin a ÃcritÂ:
>> On Wed,  6 Jun 2018 14:21:08 +0000 (UTC)
>> Christophe Leroy <christophe.leroy@xxxxxx> wrote:
>> 
>>> scaled cputime is only meaningfull when the processor has
>>> SPURR and/or PURR, which means only on PPC64.
>>>
> 
> [...]
> 
>> 
>> I wonder if we could make this depend on PPC_PSERIES or even
>> PPC_SPLPAR as well? (That would be for a later patch)
> 
> Can we go further on this ?
> 
> Do we know exactly which configuration support scaled cputime, in 
> extenso have SPRN_SPURR and/or SPRN_PURR ?
> 
> Ref https://github.com/linuxppc/issues/issues/171

Unfortunately I don't know enough about the timing stuff and who
uses it. SPURR is available on all configurations (guest, bare metal),
so it could account scaled time there too. I guess better just leave
it for now.

Thanks,
Nick