From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757366AbcHCBFK (ORCPT ); Tue, 2 Aug 2016 21:05:10 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:24418 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1757220AbcHCBFF (ORCPT ); Tue, 2 Aug 2016 21:05:05 -0400 X-IronPort-AV: E=Sophos;i="5.22,518,1449504000"; d="scan'208";a="9452465" From: Zhou Wenjian To: CC: , , , Subject: [PATCH v3 2/2] Documentation: kdump: add description of bringing up SMP dump-capture kernel Date: Wed, 3 Aug 2016 08:59:12 +0800 Message-ID: <1470185952-23477-2-git-send-email-zhouwj-fnst@cn.fujitsu.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1470185952-23477-1-git-send-email-zhouwj-fnst@cn.fujitsu.com> References: <1470185952-23477-1-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: 2978A42CA547.A30F4 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 SMP dump-capture kernel is useful to improve the performance of kdump in some cases. So add the description of bringing up SMP dump-capture kernel. Signed-off-by: Zhou Wenjian --- Documentation/kdump/kdump.txt | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt index 4aa194e..948b42d 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, we should replace it by nr_cpus to save memory if supported by the current ARCH, such as x86. +* We should bring up a SMP dump-capture kernel if we intend to use + multi-threads programs with it, such as parallel dump feature of + makedumpfile. Otherwise, the multi-threads program may have a great + performance degradation. To bring up a SMP dump-capture kernel, we + should specify maxcpus\nr_cpus and disable_cpu_apic=[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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from [59.151.112.132] (helo=heian.cn.fujitsu.com) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bUkYM-0002dX-7L for kexec@lists.infradead.org; Wed, 03 Aug 2016 01:00:59 +0000 From: Zhou Wenjian Subject: [PATCH v3 2/2] Documentation: kdump: add description of bringing up SMP dump-capture kernel Date: Wed, 3 Aug 2016 08:59:12 +0800 Message-ID: <1470185952-23477-2-git-send-email-zhouwj-fnst@cn.fujitsu.com> In-Reply-To: <1470185952-23477-1-git-send-email-zhouwj-fnst@cn.fujitsu.com> References: <1470185952-23477-1-git-send-email-zhouwj-fnst@cn.fujitsu.com> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: linux-kernel@vger.kernel.org Cc: dyoung@redhat.com, d.hatayama@jp.fujitsu.com, kexec@lists.infradead.org, bhe@redhat.com SMP dump-capture kernel is useful to improve the performance of kdump in some cases. So add the description of bringing up SMP dump-capture kernel. Signed-off-by: Zhou Wenjian --- Documentation/kdump/kdump.txt | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt index 4aa194e..948b42d 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, we should replace it by nr_cpus to save memory if supported by the current ARCH, such as x86. +* We should bring up a SMP dump-capture kernel if we intend to use + multi-threads programs with it, such as parallel dump feature of + makedumpfile. Otherwise, the multi-threads program may have a great + performance degradation. To bring up a SMP dump-capture kernel, we + should specify maxcpus\nr_cpus and disable_cpu_apic=[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 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec