linux-kernel - Re: [PATCH] x86/tsc: Use topology_max

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Message-ID: <f9da97d86e5599edca74fa859053ba9caf2b4d9c.camel@intel.com>
Date: Sun, 17 Mar 2024 12:00:26 +0000
From: "Zhang, Rui" <rui.zhang@...el.com>
To: "Hansen, Dave" <dave.hansen@...el.com>, "bp@...en8.de" <bp@...en8.de>,
	"x86@...nel.org" <x86@...nel.org>, "peterz@...radead.org"
	<peterz@...radead.org>, "hpa@...or.com" <hpa@...or.com>, "mingo@...hat.com"
	<mingo@...hat.com>, "tglx@...utronix.de" <tglx@...utronix.de>,
	"paulmck@...nel.org" <paulmck@...nel.org>, "longman@...hat.com"
	<longman@...hat.com>, "Tang, Feng" <feng.tang@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC: "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>
Subject: Re: [PATCH] x86/tsc: Use topology_max_packages() to get package
 number

On Fri, 2024-03-15 at 10:58 -0700, Dave Hansen wrote:
> On 3/15/24 04:26, Feng Tang wrote:
> > Thomas' recent patchset of refactoring x86 topology code introduces
> > topology_max_package(), 

s/topology_max_package/topology_max_packages

And topology_max_packages() is not new. The patch set actually
improves/fixes it.


> 
> I also did a big *gulp* when I saw this:
> 
>         #define topology_max_packages() (__max_logical_packages)
> 
> and:
> 
> >         /*
> >          * Today neither Intel nor AMD support heterogeneous
> > systems so
> >          * extrapolate the boot cpu's data to all packages.
> >          */
> >         ncpus = cpu_data(0).booted_cores *
> > topology_max_smt_threads();
> >         __max_logical_packages = DIV_ROUND_UP(total_cpus, ncpus);
> 
> Because Intel obviously has heterogeneous systems today.
> 
Dave, I think you were checking the old code.
Please refer to commit 090610ba704a ("x86/cpu/topology: Use topology
bitmaps for sizing"), which is just merged in this merge window.

thanks,
rui