You might like to try Java Management Extensions and use JDK tools like Jconsole to measure CF Java and Tomcat metrics.
Thanks, I will look into that. Frankly, this issue seems like just another "bug" in CF10.
anyone found a solution to this problem ?
I found the answer here : ColdFusion 11 Metrics Log NULL values | Chris Tierney
Change the connector port in CFIDE (just below where you check "enable metrics logging" to the one set as the AJP connector port in server.xml - often 8012. You'll have to restart coldfusion.
Lots of ways to double check that, i used
grep -ir 'connector port' /opt/coldfusion10/