path: root/Documentation/kdump
diff options
authorZhou Wenjian <>2016-09-19 13:59:49 +0800
committerJonathan Corbet <>2016-09-20 18:02:54 -0600
commitebf137f6703bc2cb055f4c000adc99e6ece4485d (patch)
tree035e0af490a062d7e8b18b5d16b1abe3cb1c46cd /Documentation/kdump
parent3dfb4c1bf049535c82843fc4f9c37b635fe6494e (diff)
Documentation: kdump: Add description of enable multi-cpus support
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: Jonathan Corbet <>
Diffstat (limited to 'Documentation/kdump')
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index f7ef34065d54..b0eb27b956d9 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