On 08/26/15 at 04:18pm, "Zhou, Wenjian/周文剑" wrote:
Hello Dave,
On 08/26/2015 03:59 PM, Dave Young wrote:
>Hi,
>
>On 08/25/15 at 04:43pm, Zhou Wenjian wrote:
>>A new feature that doing compressing and writing by multi-threads
>>has been added in makedumpfile. The thread num is specified by
>>"--num-threads NUM". According to its implementation, there will
>>be performance degradation if the threads are more than cpus.
>>So we should check it.
>>
>>Signed-off-by: Zhou wenjian <zhouwj-fnst(a)cn.fujitsu.com>
>>---
>> kdumpctl | 15 +++++++++++++++
>> 1 files changed, 15 insertions(+), 0 deletions(-)
>>
>>diff --git a/kdumpctl b/kdumpctl
>>index b504734..fd2abe4 100755
>>--- a/kdumpctl
>>+++ b/kdumpctl
>>@@ -259,6 +259,21 @@ check_config()
>> esac
>> done < $KDUMP_CONFIG_FILE
>>
>>+ grep "^core_collector.*makedumpfile" $KDUMP_CONFIG_FILE | grep -q
"num-threads"
>>+ if [ $? -eq 0 ];then
>>+ local nr_cpus=1
>>+ local num_threads=0
>>+ local core_collector=`grep "^core_collector" $KDUMP_CONFIG_FILE`
>>+
>>+ num_threads=`echo ${core_collector#*--num-threads} | awk '{print
$1}'`
>>+ nr_cpus=`echo ${KDUMP_COMMANDLINE_APPEND#*nr_cpus=} | awk '{print
$1}'`
>>+
>>+ if [ $num_threads -ge $nr_cpus ];then
>>+ echo "The num_threads:$num_threads(specified in /etc/kdump.conf) should
be less than nr_cpus:$nr_cpus(specified in /etc/sysconfig/kdump)"
>>+ echo "or makedumpfile may have bad performance!"
>
>It is better to do this in makedumpfile source code instead of adding
>these warnings specific for num-threads here.
>
I have one more question.
Since multi-thread feature is associated with nr_cpus, should we do something here?
Hmm, adding it in makedumpfile will be too late for warning users. But I do not like
adding these stuff in distribution script, user should know the limitation if he
choose the thread number. How about moving it to makedumpfile --help to describe
the problem just around the num_threads option.
--
Thanks
Zhou
>>+ fi
>>+ fi
>>+
>> check_fence_kdump_config || return 1
>>
>> return 0
>>--
>>1.7.1
>>
>>_______________________________________________
>>kexec mailing list
>>kexec(a)lists.fedoraproject.org
>>https://lists.fedoraproject.org/mailman/listinfo/kexec
>>
>>