From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S938788AbcISFxK (ORCPT ); Mon, 19 Sep 2016 01:53:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59800 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932557AbcISFxD (ORCPT ); Mon, 19 Sep 2016 01:53:03 -0400 Date: Mon, 19 Sep 2016 13:52:57 +0800 From: Baoquan He To: corbet@lwn.net, akpm@linux-foundation.org Cc: linux-doc@vger.kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, xlpang@redhat.com, dyoung@redhat.com, Zhou Wenjian Subject: Re: [PATCH v10 3/3] Documentation: kdump: add description of enable multi-cpus support Message-ID: <20160919055257.GA8693@x1.redhat.com> References: <1474257665-8838-1-git-send-email-bhe@redhat.com> <1474257665-8838-4-git-send-email-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1474257665-8838-4-git-send-email-bhe@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Mon, 19 Sep 2016 05:53:02 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/19/16 at 12:01pm, Baoquan He wrote: > From: Zhou Wenjian > > 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 > Signed-off-by: Baoquan He Oh, sorry. My git config caused this Signed-off-by adding automatically. Will resend. Nack this patchset. > --- > Documentation/kdump/kdump.txt | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt > index f7ef340..b0eb27b 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 had better replace it with > 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 > -- > 2.5.5 >