linux-kernel - Re: [PATCH PATCH 1/9] x86/cpu/topology: Add x86_cpu_type to struct cpuinfo

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Message-ID: <20240618212801.GJZnH74Q4yknT-4X12@fat_crate.local>
Date: Tue, 18 Jun 2024 23:28:01 +0200
From: Borislav Petkov <bp@...en8.de>
To: Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
	daniel.sneddon@...ux.intel.com, tony.luck@...el.com,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-perf-users@...r.kernel.org,
	Josh Poimboeuf <jpoimboe@...nel.org>,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>,
	"Liang, Kan" <kan.liang@...ux.intel.com>,
	Andrew Cooper <andrew.cooper3@...rix.com>
Subject: Re: [PATCH PATCH 1/9] x86/cpu/topology: Add x86_cpu_type to struct
 cpuinfo_topology

On Mon, Jun 17, 2024 at 02:11:26AM -0700, Pawan Gupta wrote:
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -95,6 +95,9 @@ struct cpuinfo_topology {
>  	// Core ID relative to the package
>  	u32			core_id;
>  
> +	// CPU-type e.g. performance, efficiency etc.
> +	u8			cpu_type;
> +
>  	// Logical ID mappings
>  	u32			logical_pkg_id;
>  	u32			logical_die_id;
> diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
> index abe3a8f22cbd..b28ad9422afb 100644
> --- a/arch/x86/include/asm/topology.h
> +++ b/arch/x86/include/asm/topology.h
> @@ -41,6 +41,14 @@
>  /* Mappings between logical cpu number and node number */
>  DECLARE_EARLY_PER_CPU(int, x86_cpu_to_node_map);
>  
> +#define X86_CPU_TYPE_INTEL_SHIFT	24
> +
> +enum x86_topo_cpu_type {
> +	X86_CPU_TYPE_UNKNOWN		= 0,
> +	X86_CPU_TYPE_INTEL_ATOM		= 0x20,
> +	X86_CPU_TYPE_INTEL_CORE		= 0x40,

Can we unify those core types and do our own (our == Linux) defines instead of
using Intels or AMDs?

There will be AMD variants too soon:

https://lore.kernel.org/r/7aad57a98b37fa5893d4fe602d3dcef5c3f755d5.1718606975.git.perry.yuan@amd.com

so can we have generic defines like

PERF_CORE
EFF_CORE
bla_CORE

and so on

?

And then map each vendor's types to the Linux types?

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette