From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946008AbcHRDNW (ORCPT ); Wed, 17 Aug 2016 23:13:22 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:48344 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1945958AbcHRDNT (ORCPT ); Wed, 17 Aug 2016 23:13:19 -0400 X-IronPort-AV: E=Sophos;i="5.22,518,1449504000"; d="scan'208";a="10029199" From: Zhou Wenjian To: CC: , , , , , , , , Subject: [PATCH v9 2/2] Documentation: kdump: add description of enable multi-cpus support Date: Thu, 18 Aug 2016 11:11:47 +0800 Message-ID: <1471489907-27737-3-git-send-email-zhouwj-fnst@cn.fujitsu.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1471489907-27737-1-git-send-email-zhouwj-fnst@cn.fujitsu.com> References: <1471489907-27737-1-git-send-email-zhouwj-fnst@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.167.226.48] X-yoursite-MailScanner-ID: D41A242BC505.A8740 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: zhouwj-fnst@cn.fujitsu.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org multi-cpu support is useful to improve the performance of kdump in some cases. So add the description of enable multi-cpu support in dump-capture kernel. Signed-off-by: Zhou Wenjian Acked-by: Baoquan He Acked-by: Xunlei Pang --- Documentation/kdump/kdump.txt | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt index d900080..31e6b88 100644 --- a/Documentation/kdump/kdump.txt +++ b/Documentation/kdump/kdump.txt @@ -396,6 +396,13 @@ Notes on loading the dump-capture kernel: Note, though maxcpus always works, you should replace it by nr_cpus to save memory if supported by the current ARCH, such as x86. +* You should enable multi-cpu support in dump-capture kernel if you intend + to use multi-thread programs with it, such as parallel dump feature of + makedumpfile. Otherwise, the multi-thread program may have a great + performance degradation. To enable multi-cpu support, you should bring up an + SMP dump-capture kernel and specify maxcpus/nr_cpus, disable_cpu_apicid=[X] + options while loading it. + * For s390x there are two kdump modes: If a ELF header is specified with the elfcorehdr= kernel parameter, it is used by the kdump kernel as it is done on all other architectures. If no elfcorehdr= kernel parameter is -- 1.8.3.1