From: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
To: <linux-kernel@vger.kernel.org>
Cc: <kexec@lists.infradead.org>, <bhe@redhat.com>,
<dyoung@redhat.com>, <d.hatayama@jp.fujitsu.com>
Subject: [PATCH 2/2] Documentation: kdump: add description of bringing up SMP dump-capture kernel
Date: Fri, 29 Jul 2016 11:23:15 +0800 [thread overview]
Message-ID: <1469762595-1085-2-git-send-email-zhouwj-fnst@cn.fujitsu.com> (raw)
In-Reply-To: <1469762595-1085-1-git-send-email-zhouwj-fnst@cn.fujitsu.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 <zhouwj-fnst@cn.fujitsu.com>
---
Documentation/kdump/kdump.txt | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index 9a77247..155a63c 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -394,6 +394,12 @@ Notes on loading the dump-capture kernel:
dump. Hence generally it is useful either to build a UP dump-capture
kernel or specify nr_cpus=1 option while loading dump-capture kernel.
+* 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 nr_cpus=[X] and
+ disable_cpu_apic=[Y] 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
next prev parent reply other threads:[~2016-07-29 3:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-29 3:23 [PATCH 1/2] Documentation: kdump: update maxcpus to nr_cpus Zhou Wenjian
2016-07-29 3:23 ` Zhou Wenjian [this message]
2016-07-30 2:19 ` Baoquan He
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