From: Ingo Molnar <mingo@kernel.org>
To: Dave Jones <davej@redhat.com>,
x86@kernel.org, Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: disabled APICs being counted as processors ?
Date: Sat, 25 Jan 2014 08:41:07 +0100 [thread overview]
Message-ID: <20140125074107.GA10565@gmail.com> (raw)
In-Reply-To: <20140123221316.GA23367@redhat.com>
* Dave Jones <davej@redhat.com> wrote:
> I have a system with 4 cores (configured with CONFIG_NR_CPUS=4) that shows during boot..
>
> [ 0.000000] smpboot: 8 Processors exceeds NR_CPUS limit of 4
>
> it looks like this is because..
>
> [ 0.000000] ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] enabled)
> [ 0.000000] ACPI: LAPIC (acpi_id[0x02] lapic_id[0x02] enabled)
> [ 0.000000] ACPI: LAPIC (acpi_id[0x03] lapic_id[0x04] enabled)
> [ 0.000000] ACPI: LAPIC (acpi_id[0x04] lapic_id[0x06] enabled)
> [ 0.000000] ACPI: LAPIC (acpi_id[0x05] lapic_id[0xff] disabled)
> [ 0.000000] ACPI: LAPIC (acpi_id[0x06] lapic_id[0xff] disabled)
> [ 0.000000] ACPI: LAPIC (acpi_id[0x07] lapic_id[0xff] disabled)
> [ 0.000000] ACPI: LAPIC (acpi_id[0x08] lapic_id[0xff] disabled)
>
> Should the CPU counting code be ignoring those disabled APICs ?
Hm, so to the kernel it looks like as if those were 'possible CPUs',
in theory hotpluggable. Not sure what they are - disabled cores in an
8-core system? Or BIOS reporting crap?
But perhaps the boot message could be improved to say something like:
> [ 0.000000] smpboot: 8 possible processors exceeds NR_CPUS limit of 4
?
Thanks,
Ingo
next prev parent reply other threads:[~2014-01-25 7:41 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-23 22:13 disabled APICs being counted as processors ? Dave Jones
2014-01-25 7:41 ` Ingo Molnar [this message]
2014-01-25 15:30 ` Dave Jones
2014-01-26 6:41 ` David Rientjes
2014-01-26 8:36 ` Ingo Molnar
2014-01-26 8:51 ` Yinghai Lu
2014-01-26 9:09 ` Ingo Molnar
2014-01-26 9:23 ` David Rientjes
2014-01-26 9:29 ` Ingo Molnar
2014-01-26 9:44 ` David Rientjes
2014-01-25 16:42 ` Henrique de Moraes Holschuh
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