linux-kernel - Re: [PATCH 0/9] Add CPU-type to topology

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Date: Thu, 27 Jun 2024 08:26:09 -0700
From: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
To: Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>
Cc: Dave Hansen <dave.hansen@...el.com>,
	Brice Goglin <brice.goglin@...il.com>,
	srinivas pandruvada <srinivas.pandruvada@...ux.intel.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
	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>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	"Liang, Kan" <kan.liang@...ux.intel.com>,
	Andrew Cooper <andrew.cooper3@...rix.com>
Subject: Re: [PATCH 0/9] Add CPU-type to topology

On Thu, Jun 27, 2024 at 06:22:30AM -0700, Pawan Gupta wrote:
> On Thu, Jun 27, 2024 at 05:51:54AM -0700, Ricardo Neri wrote:
> > ARM gives userspace specific details. This makes more sense to me. Instead
> > of reading these details, user space would have to infer these details if
> > a CPU type was given in sysfs.
> > 
> > Having said that, Intel does have a CPUID leaf that gives the CPU type. Such
> > leaf also has a "Native Model ID". Exposing only the CPU type may not be
> > sufficient.
> 
> Do we know if there are applications that would benefit from this information?

Probably not, but exposing it would follow ARM's approach of exposing the
raw details and let user space consume it as it wishes instead of having
kernel give an answer that could probably be imcomplete.

> 
> We agreed to leave sysfs for another series. I will be sending v2 soon.

It is fine, just wanted to express some opinions. :)