Timespan of a node calculation

Hi all,
I am creating custom nodes to get a processing time of a node for debug.
I created two custom node getting current time, and inserted a debugging node between the nodes.
And then I got the difference of the time.
But the current time is not updated without the modification of the script.
Does somebody know the way of how to get a current time for the every execution ?
Any help will be appreciated.

Thanks and regards,

Hi Kulkul,
Thank you for your presenting sample.
It’s very helpful.