Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763492AbZFPGYX (ORCPT ); Tue, 16 Jun 2009 02:24:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752053AbZFPGYJ (ORCPT ); Tue, 16 Jun 2009 02:24:09 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:47155 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751453AbZFPGYI (ORCPT ); Tue, 16 Jun 2009 02:24:08 -0400 Date: Mon, 15 Jun 2009 23:23:18 -0700 From: Andrew Morton To: Gautham R Shenoy Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Balbir Singh , Rusty Russel , Paul E McKenney , Nathan Lynch , Ingo Molnar , Venkatesh Pallipadi , Vaidyanathan Srinivasan , Dipankar Sarma , Shoahua Li Subject: Re: [RFD PATCH 0/4] cpu: Bulk CPU Hotplug support. Message-Id: <20090615232318.74b099a6.akpm@linux-foundation.org> In-Reply-To: <20090616053431.30891.18682.stgit@sofia.in.ibm.com> References: <20090616053431.30891.18682.stgit@sofia.in.ibm.com> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 769 Lines: 23 On Tue, 16 Jun 2009 11:08:39 +0530 Gautham R Shenoy wrote: > Currently on a ppc64 box with 16 CPUs, the time taken for > a individual cpu-hotplug operation is as follows. > > # time echo 0 > /sys/devices/system/cpu/cpu2/online > real 0m0.025s > user 0m0.000s > sys 0m0.002s > > # time echo 1 > /sys/devices/system/cpu/cpu2/online > real 0m0.021s > user 0m0.000s > sys 0m0.000s Surprised. Do people really online and offline CPUs frequently enough for this to be a problem? -- 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/