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

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Date: Mon, 18 Mar 2024 08:08:57 -0700
From: Dave Hansen <dave.hansen@...el.com>
To: "Zhang, Rui" <rui.zhang@...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 3/17/24 05:00, Zhang, Rui wrote:
>> 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.

You're 100% right.  I was looking at a weeks-old tree.  Sorry for the noise.