linux-kernel - Re: AMD Ryzen 7 PRO 7735U: 8 instead of 16 CPUs?

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Message-ID: <ghplhl1qm2.fsf@gouders.net>
Date: Wed, 09 Apr 2025 14:11:49 +0200
From: Dirk Gouders <dirk@...ders.net>
To: Borislav Petkov <bp@...en8.de>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Linux Kernel
 <linux-kernel@...r.kernel.org>,
        Linux x86 <x86@...nel.org>
Subject: Re: AMD Ryzen 7 PRO 7735U: 8 instead of 16 CPUs?

Borislav Petkov <bp@...en8.de> writes:

> On Wed, Apr 09, 2025 at 12:49:14PM +0200, Dirk Gouders wrote:
>> I got new hardware and after setting up everything, I was wondering why
>> I don't see the expected 16 CPUs in top(1) or /proc/cpuinfo...
>
> Send full dmesg pls.

Oh well, thanks for the hint: CONFIG_NR_CPUS=8

And if I had analyzed that better, I would have noticed myself:

[    0.059658] CPU topo: CPU limit of 8 reached. Ignoring further CPUs
...
[    0.059709] CPU topo: Rejected CPUs 8


OK, next recipients are the amdgpu folks with a trace that has a higher
chance the problem isn't me...

Best regards,

Dirk