Re: [PATCH v5 2/2] Documentation: kdump: add description of enable multi-cpus support

From: Dave Young
Date: Wed Aug 10 2016 - 14:43:41 EST


On 08/10/16 at 02:22pm, Zhou Wenjian wrote:
> 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 <zhouwj-fnst@xxxxxxxxxxxxxx>
> Acked-by: Baoquan He <bhe@xxxxxxxxxx>
> ---
> Documentation/kdump/kdump.txt | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> index b474060..9c8d18e 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 enable multi-cpu support in dump-capture kernel if we 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, we should bring up
> + a SMP dump-capture kernel and specify maxcpus\nr_cpus, disable_cpu_apic=[X]
> + options while loading it.

Again, please replace "we" with second person "you"..

> +
> * 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
>
>
>