Thanks for your work.
It seems its a V2. So please prefix with PATCH V2 and resend.
You can use:
git format-patch --subject-prefix="PATCH V2"
On 15/09/2015:10:34:14 AM, Zhou Wenjian wrote:
Add descriptions of parallel dumping and how to use it.
Signed-off-by: Zhou Wenjian <zhouwj-fnst(a)cn.fujitsu.com>
And since its a single patch so, after you have done format-patch, please write
a change log here as it has been written in
kexec-kdump-howto.txt | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/kexec-kdump-howto.txt b/kexec-kdump-howto.txt
index 05b497f..97a319c 100644
@@ -616,6 +616,38 @@ options are copied from /proc/cmdline. In general it is best to
command line options using "KDUMP_COMMANDLINE_APPEND=" instead of replacing
the original command line completely.
+Parallel Dumping Operation
+Kexec allows kdump using multiple cpus. So parallel feature can accelerate
+dumping substantially, especially in executing compress and filter.
+ 1."makedumpfile -c --num-threads [THREAD_NUM] /proc/vmcore dumpfile"
+ 2."makedumpfile -c /proc/vmcore dumpfile",
+ 1 has better performance than 2, if THREAD_NUM is larger than two
+ and the usable cpus number is larger than THREAD_NUM.
+Notes on how to use multiple cpus on a capture kernel on x86 system:
+Make sure that you are using a sufficiently new kernel version that supports
I remember Dave suggested to avoid "sufficiently new". So, if you do not agree
with some comment then please let that know, otherwise reviewer will assume that
+disable_cpu_apicid kernel option as a capture kernel, which is
+avoid x86 specific hardware issue (*). The disable_cpu_apicid kernel option
+is automatically appended by kdumpctl script and is ignored if the kernel
+doesn't support it.
+You need to specify how many cpus to be used in a capture kernel by specifying
+the number of cpus in nr_cpus kernel option in /etc/sysconfig/kdump. nr_cpus
+is 1 at default.
+You should use necessary and suffcient amount of cpus on a capture kernel.
I still think that "number of cpus" would have been a better choice than
Other than above two minor thing, patch looks fine to me.