From: Gabriel C <nix.or.die@googlemail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Uladzislau Rezki <urezki@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>
Subject: Re: nr_cpu_ids vs AMD 3970x(32 physical CPUs)
Date: Fri, 3 Jul 2020 20:36:02 +0200 [thread overview]
Message-ID: <CAEJqkgh0samT7TkLqhBLw5x8-bV1iAX1a-PHxtgruMgpdsfvBQ@mail.gmail.com> (raw)
In-Reply-To: <20200703174539.GA4800@hirez.programming.kicks-ass.net>
Am Fr., 3. Juli 2020 um 19:45 Uhr schrieb Peter Zijlstra <peterz@infradead.org>:
>
> On Fri, Jul 03, 2020 at 07:07:39PM +0200, Gabriel C wrote:
>
> > I boot all the boxes restricting the cores to the correct count on the
> > command line.
>
> This, because you're right about the wasted memory.
>
> > Wasted resource or not, this is still a bug IMO.
>
> Yeah, but not one we can do much about I think. It is the BIOS saying it
> wants more because it expects someone to come along and stick another
> CPU in.
>
> Possible we could say that for single socket machines overprovisioning
> is 'silly', but then, I've no idea how to detect that. You'll need to
> find an ACPI person.
I know the EPYC box got that problem too initially, it reported twice
the cores and twice the sockets,
but got fixed in some kernel versions.
https://lkml.org/lkml/2018/5/20/102
I never really looked at how this is calculated but I still believe
there is a bug somewhere.
next prev parent reply other threads:[~2020-07-03 18:36 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
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 [this message]
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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