Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761197Ab2BNVAB (ORCPT ); Tue, 14 Feb 2012 16:00:01 -0500 Received: from ozlabs.org ([203.10.76.45]:39233 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761036Ab2BNVAA convert rfc822-to-8bit (ORCPT ); Tue, 14 Feb 2012 16:00:00 -0500 From: Rusty Russell To: Tony Luck , "Srivatsa S. Bhat" Cc: Andrew Morton , Venkatesh Pallipadi , KOSAKI Motohiro , KOSAKI Motohiro , Mike Travis , "Paul E. McKenney" , "Rafael J. Wysocki" , Paul Gortmaker , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Avoid mask based num_possible_cpus and num_online_cpus -v5 In-Reply-To: References: <1328055439-9441-1-git-send-email-venki@google.com> <20120201140125.c656df41.akpm@linux-foundation.org> <87d39xj955.fsf@rustcorp.com.au> <4F3971A1.5010305@linux.vnet.ibm.com> <4F39763D.3070609@linux.vnet.ibm.com> User-Agent: Notmuch/0.6.1-1 (http://notmuchmail.org) Emacs/23.3.1 (i686-pc-linux-gnu) Date: Tue, 14 Feb 2012 19:55:36 +1030 Message-ID: <87wr7pbwbz.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1256 Lines: 31 On Mon, 13 Feb 2012 13:57:45 -0800, Tony Luck wrote: > On Mon, Feb 13, 2012 at 12:44 PM, Srivatsa S. Bhat > wrote: > > IOW, what output do you see from the following printk from > > arch/ia64/kernel/smpboot.c? > > > > printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n", > >         (int)num_online_cpus(), bogosum/(500000/HZ), (bogosum/(5000/HZ))%100); > > That is a complicated question - because linux-next also has patches > by Arjan that > change how (when) cpus are brought online. Initially I blamed his > patches and tried > reverting them ... and saw the symptom you are wondering about (message said > "Total of 1 processors", but the BogoMIPs was a number big enough to be all of > them. Thanks to you, I can now understand why. > > Fix will be to stop ia64 from messing directly with cpu_online_map? Yes, and the other architectures. We're well within reach of removing cpu_*_map now I think. Cheers, Rusty. -- 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/