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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 v2] Documentation: kdump: add description of bringing up SMP dump-capture kernel
Date: Mon, 1 Aug 2016 08:23:08 +0800	[thread overview]
Message-ID: <1470010988-18050-1-git-send-email-zhouwj-fnst@cn.fujitsu.com> (raw)

v1->v2: change nr_cpus to maxcpus

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 88ff63d..c5762b7 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 maxcpus=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 maxcpus=[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

WARNING: multiple messages have this Message-ID (diff)
From: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
To: linux-kernel@vger.kernel.org
Cc: dyoung@redhat.com, d.hatayama@jp.fujitsu.com,
	kexec@lists.infradead.org, bhe@redhat.com
Subject: [PATCH v2] Documentation: kdump: add description of bringing up SMP dump-capture kernel
Date: Mon, 1 Aug 2016 08:23:08 +0800	[thread overview]
Message-ID: <1470010988-18050-1-git-send-email-zhouwj-fnst@cn.fujitsu.com> (raw)

v1->v2: change nr_cpus to maxcpus

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 88ff63d..c5762b7 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 maxcpus=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 maxcpus=[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




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             reply	other threads:[~2016-08-01  0:26 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-01  0:23 Zhou Wenjian [this message]
2016-08-01  0:23 ` [PATCH v2] Documentation: kdump: add description of bringing up SMP dump-capture kernel Zhou Wenjian
2016-08-02  7:46 ` Baoquan He
2016-08-02  7:46   ` Baoquan He
2016-08-02  8:49   ` "Zhou, Wenjian/周文剑"
2016-08-02  8:49     ` "Zhou, Wenjian/周文剑"
2016-08-02 14:09     ` Baoquan He
2016-08-02 14:09       ` Baoquan He

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