Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752156AbaAYPbF (ORCPT ); Sat, 25 Jan 2014 10:31:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:14885 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751708AbaAYPbC (ORCPT ); Sat, 25 Jan 2014 10:31:02 -0500 Date: Sat, 25 Jan 2014 10:30:48 -0500 From: Dave Jones To: Ingo Molnar Cc: x86@kernel.org, Linux Kernel Subject: Re: disabled APICs being counted as processors ? Message-ID: <20140125153048.GA8536@redhat.com> Mail-Followup-To: Dave Jones , Ingo Molnar , x86@kernel.org, Linux Kernel References: <20140123221316.GA23367@redhat.com> <20140125074107.GA10565@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140125074107.GA10565@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 25, 2014 at 08:41:07AM +0100, Ingo Molnar wrote: > > * Dave Jones 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 It's not possible though. It's an i5-4670T, in a single socket board. It doesn't even have hyperthreading. http://ark.intel.com/products/75050/Intel-Core-i5-4670T-Processor-6M-Cache-up-to-3_30-GHz Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/