From: Peter Zijlstra <peterz@infradead.org>
To: Uladzislau Rezki <urezki@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
GregKroah-Hartmangregkh@linuxfoundation.org
Subject: Re: nr_cpu_ids vs AMD 3970x(32 physical CPUs)
Date: Fri, 3 Jul 2020 18:56:27 +0200 [thread overview]
Message-ID: <20200703165627.GG4781@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200703155749.GA6255@pc636>
On Fri, Jul 03, 2020 at 05:57:49PM +0200, Uladzislau Rezki wrote:
> Hello, folk.
>
> I have a system based on AMD 3970x CPUs. It has 32 physical cores
> and 64 threads. It seems that "nr_cpu_ids" variable is not correctly
> set on latest 5.8-rc3 kernel. Please have a look below on dmesg output:
>
> <snip>
> urezki@pc638:~$ sudo dmesg | grep 128
> [ 0.000000] IOAPIC[0]: apic_id 128, version 33, address 0xfec00000, GSI 0-23
> [ 0.000000] smpboot: Allowing 128 CPUs, 64 hotplug CPUs
This is your BIOS saying it needs 128 ids, 64 of which are 'empty'.
I have a box like that as well, if it bothers you boot with:
"possible_cpus=64" or something.
next prev parent reply other threads:[~2020-07-03 16:56 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-03 15:57 nr_cpu_ids vs AMD 3970x(32 physical CPUs) Uladzislau Rezki
2020-07-03 16:56 ` Peter Zijlstra [this message]
2020-07-03 17:09 ` Uladzislau Rezki
2020-07-03 17:38 ` Peter Zijlstra
2020-07-03 19:26 ` Uladzislau Rezki
2020-07-03 17:07 ` Gabriel C
2020-07-03 17:24 ` Uladzislau Rezki
2020-07-03 17:45 ` Peter Zijlstra
2020-07-03 18:36 ` Gabriel C
2020-07-03 19:05 ` peter enderborg
2020-07-03 19:28 ` Uladzislau Rezki
2020-07-03 20:08 ` Linus Torvalds
2020-07-03 21:20 ` Uladzislau Rezki
2020-07-03 21:51 ` Matthew Wilcox
2020-07-03 22:22 ` Uladzislau Rezki
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