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 at 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
