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 at cn.fujitsu.com> --- 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
