I often wonder whether the plugin I developed is a heavy plugin or not, I've always used NoLagg's tester for it. But I actually wondered if someone knows an even better program to measure this since I won't be running NoLagg. I only use it for testing.
Use timings. (No plugin needed if using spigot) Do the following: /timings on After 5-10 minutes do /timings paste Then /timings off
It'll link you to a webpage. Heres a sample output from my server 14:35:20 [INFO] Your timings have been pasted to http://paste.ubuntu.com/5849688/ 14:35:20 [INFO] You can view the results at http://aikar.co/timings.php?url=5849688 Going to the second link will give you a near full picture of what your plugin is doing when you click on "See Rest" (Mine is very small as I only just quickly did that for a few seconds).