Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754330Ab2BMV5r (ORCPT ); Mon, 13 Feb 2012 16:57:47 -0500 Received: from mail-iy0-f174.google.com ([209.85.210.174]:46517 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754207Ab2BMV5q convert rfc822-to-8bit (ORCPT ); Mon, 13 Feb 2012 16:57:46 -0500 MIME-Version: 1.0 In-Reply-To: <4F39763D.3070609@linux.vnet.ibm.com> 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> Date: Mon, 13 Feb 2012 13:57:45 -0800 Message-ID: Subject: Re: [PATCH] Avoid mask based num_possible_cpus and num_online_cpus -v5 From: Tony Luck To: "Srivatsa S. Bhat" Cc: Rusty Russell , Andrew Morton , Venkatesh Pallipadi , KOSAKI Motohiro , KOSAKI Motohiro , Mike Travis , "Paul E. McKenney" , "Rafael J. Wysocki" , Paul Gortmaker , linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1038 Lines: 24 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? -Tony -- 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/