Hi Zhou,
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
https://lists.fedoraproject.org/pipermail/kexec/2015-August/002271.html
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
--- a/kexec-kdump-howto.txt
+++ b/kexec-kdump-howto.txt
@@ -616,6 +616,38 @@ options are copied from /proc/cmdline. In general it is best to
append
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.
+For example:
+
+ 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
you agreed.
+disable_cpu_apicid kernel option as a capture kernel, which is
needed to
+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
"amount
of cpus".
Other than above two minor thing, patch looks fine to me.
~Pratyush