Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755851Ab2JPFOt (ORCPT ); Tue, 16 Oct 2012 01:14:49 -0400 Received: from mga01.intel.com ([192.55.52.88]:58948 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755683Ab2JPFOr convert rfc822-to-8bit (ORCPT ); Tue, 16 Oct 2012 01:14:47 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.80,593,1344236400"; d="scan'208";a="234353663" From: "Yu, Fenghua" To: HATAYAMA Daisuke CC: "linux-kernel@vger.kernel.org" , "kexec@lists.infradead.org" , "x86@kernel.org" , "mingo@elte.hu" , "tglx@linutronix.de" , "hpa@zytor.com" , "Brown, Len" , "vgoyal@redhat.com" , "ebiederm@xmission.com" , "grant.likely@secretlab.ca" , "rob.herring@calxeda.com" Subject: RE: [PATCH v1 0/2] x86, apic: Disable BSP if boot cpu is AP Thread-Topic: [PATCH v1 0/2] x86, apic: Disable BSP if boot cpu is AP Thread-Index: AQHNq1e0cdLRWLkn60qkdlE2ARg+FJe7WVDQgAB8b4D//4uFoA== Date: Tue, 16 Oct 2012 05:14:46 +0000 Message-ID: <3E5A0FA7E9CA944F9D5414FEC6C7122030B0DD91@ORSMSX105.amr.corp.intel.com> References: <20121016043357.20003.5885.stgit@localhost6.localdomain6> <3E5A0FA7E9CA944F9D5414FEC6C7122030B0DD68@ORSMSX105.amr.corp.intel.com> <20121016.140313.279437418.d.hatayama@jp.fujitsu.com> In-Reply-To: <20121016.140313.279437418.d.hatayama@jp.fujitsu.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.22.254.138] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1514 Lines: 47 > >> My motivation is to use multiple CPUs in order to quickly generate > >> crash dump on the machine with huge amount of memory. I assume such > >> machine tends to also have a lot of CPUs. So disabling one CPU would > >> be no problem. > > > > Luckily you don't need to disable any CPU to archive your goal with > > the BSP hotplug pachest:) > > > > On a dual core/single thread machine, this means you get 100% > performance > > boost with BSP's help. > > > > Plus crash dump kernel code is better structured by not treating BSP > > specially. > > > > Hello Fenghua. > > I've of course noticed your patch set and locally tested, but I saw > NMI to BSP failed in the 2nd kernel. I'll send a log to you later. > > BTW, I tested with your previous v8 patch set. Did you change > something during v8 to v9 relevant to this issue? In the patch 0/12 in v9, I describe what change is in v9 on the top of v8: v9: Add Intel vendor check to support the feature on Intel platforms only. Did you see the BSP wake up failure on the latest tip tree? There is a rcu regression issue which prevents BSP from waking up in 3.6.0. The issue has been fixed on 10/12. The commit is a4fbe35a. Please make sure your tip tree has this commit. Thanks. -Fenghua Thanks. -Fenghua -- 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/