Re: [PATCH 2/2] powercap/rapl: add support for denverton

From: Dave Hansen
Date: Tue May 31 2016 - 18:19:38 EST


On 05/31/2016 01:41 PM, Jacob Pan wrote:
> --- a/drivers/powercap/intel_rapl.c
> +++ b/drivers/powercap/intel_rapl.c
> @@ -1137,6 +1137,7 @@ static const struct x86_cpu_id rapl_ids[] __initconst = {
> RAPL_CPU(0x57, rapl_defaults_hsw_server),/* Knights Landing */
> RAPL_CPU(0x8E, rapl_defaults_core),/* Kabylake */
> RAPL_CPU(0x9E, rapl_defaults_core),/* Kabylake */
> + RAPL_CPU(0x5F, rapl_defaults_core),/* Denverton micro server */
> {}
> };

Not to derail this individual patch... but do we really want to continue
open-coding CPU model/family combos all over arch/x86?

For instance, arch/x86/events/intel/core.c has:

> case 142: /* 14nm Kabylake Mobile */
> case 158: /* 14nm Kabylake Desktop */
> case 78: /* 14nm Skylake Mobile */
> case 94: /* 14nm Skylake Desktop */
> case 85: /* 14nm Skylake Server */

Which duplicates the two Kabylake family numbers from the RAPL_CPU()
context above (just in decimal instead of hex).

Should we just start sticking these things in a header like:

#define X86_INTEL_FAMILY_KABYLAKE1 0x8E
#define X86_INTEL_FAMILY_KABYLAKE2 0x9E
#define X86_INTEL_FAMILY_DENVERTON 0x5F

So we have this:

RAPL_CPU(X86_INTEL_FAMILY_DENVERTON, rapl_defaults_core),

instead of having to explain our magic number in a comment.