linux-kernel - Re: [PATCH v4 1/2] powerpc/time: Only set CONFIG_ARCH_HAS_SCALED

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Date:   Wed, 14 Aug 2019 08:31:02 +0200
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Nicholas Piggin <npiggin@...il.com>
Cc:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Frederic Weisbecker <fweisbec@...il.com>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        Segher Boessenkool <segher@...nel.crashing.org>
Subject: Re: [PATCH v4 1/2] powerpc/time: Only set
 CONFIG_ARCH_HAS_SCALED_CPUTIME on PPC64

Hi Nick,


Le 07/06/2018 à 03:43, Nicholas Piggin a écrit :
> On Wed,  6 Jun 2018 14:21:08 +0000 (UTC)
> Christophe Leroy <christophe.leroy@....fr> 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

Christophe