Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751234AbWCLVOP (ORCPT ); Sun, 12 Mar 2006 16:14:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751770AbWCLVOP (ORCPT ); Sun, 12 Mar 2006 16:14:15 -0500 Received: from bizon.gios.gov.pl ([212.244.124.8]:9618 "EHLO bizon.gios.gov.pl") by vger.kernel.org with ESMTP id S1751234AbWCLVOP (ORCPT ); Sun, 12 Mar 2006 16:14:15 -0500 Date: Sun, 12 Mar 2006 22:13:59 +0100 (CET) From: Krzysztof Oledzki X-X-Sender: olel@bizon.gios.gov.pl To: Venkatesh Pallipadi cc: Andrew Morton , linux-kernel@vger.kernel.org, Ashok Raj , Suresh B Siddha , Rajesh Shah Subject: Re: More than 8 CPUs detected and CONFIG_X86_PC cannot handle it on 2.6.16-rc6 In-Reply-To: <20060312073524.A9213@unix-os.sc.intel.com> Message-ID: References: <20060311210353.7eccb6ed.akpm@osdl.org> <20060312032523.109361c1.akpm@osdl.org> <20060312073524.A9213@unix-os.sc.intel.com> MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="-187430788-1570438749-1142198039=:19689" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2557 Lines: 74 This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. ---187430788-1570438749-1142198039=:19689 Content-Type: TEXT/PLAIN; charset=ISO-8859-2; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE On Sun, 12 Mar 2006, Venkatesh Pallipadi wrote: > On Sun, Mar 12, 2006 at 02:05:00PM +0100, Krzysztof Oledzki wrote: >> >> >> On Sun, 12 Mar 2006, Andrew Morton wrote: >> >>> Krzysztof Oledzki wrote: >>>> >>>> On Sat, 11 Mar 2006, Andrew Morton wrote: >>>> >>>>> Krzysztof Oledzki wrote: >>>>>> >>>>>> After upgrading to 2.6.16-rc6 I noticed this strange message: >>>>>> >>>>>> More than 8 CPUs detected and CONFIG_X86_PC cannot handle it. >>>>>> Use CONFIG_X86_GENERICARCH or CONFIG_X86_BIGSMP. >>>>>> >>>>>> This is a Dell PowerEdge SC1425 with two P4 Xeons with HT enabled (s= o with >>>>>> totoal of 4 logical CPUs). >>>>> >>>>> Please send full dmesg output for the failing kernel, thanks. >>>> Attached. >>>> >>>>> Which is the most-recently-tested kernel which behaved correctly? >>>> 2.6.15.6 >>> >>> OK, thanks. I assume the machine's working OK? >> >> Yes. So far no problems, only this warning. >> >>> From my reading, you have CONFIG_HOTPLUG_CPU enabled and the machine ha= s an >>> APIC. >> That is correct. >> >>> I'd expect that lots of people would hit that warning but for some >>> reason they don't - possibly because most APICs don't have sufficiently >>> high version numbers? >>> > > Actually, this warning should be seen on many other systems on well. We > use the bigsmp when there _or_ more than 8 CPUs or CPU_HOTPLUG is used. > So, in that sense the message is wrong, it should also have CPU_HOTPLUG i= n > there. Or we should make CPU_HOTPLUG depend on GENERIC_ARCH or auto selec= t > GENERIC_ARCH with hotplug at the CONFIG level. Why? I have exactly 4 HT CPUs (2 cores), no more. I use CPU hotplug so I=20 can disable or enable any of them when I want to. So, this is a classic=20 SMP system and 2.6.15 is totally happy with this. Or is there any other=20 (better?) way to disable/enable CPU (especially second logical CPU from=20 HT) on running systems? Best regards, =09=09=09=09Krzysztof Ol=EAdzki ---187430788-1570438749-1142198039=:19689-- - 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/