[PATCH v2] Add checking num-threads of makedumpfile

[Dave Young]

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 at 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.

> +		fi
> +	fi
> +
>  	check_fence_kdump_config || return 1
>  
>  	return 0
> -- 
> 1.7.1
> 
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