Just run 'onrush' from a shell prompt.
In Unix, you can make a desktop shortcut to /usr/local/rush/bin/onrush,
or under Windows, make the shortcut to c:\rush\bin\onrush.exe
The little interface should pop up, and let you control the online/offline state of the daemon.
This example shows how the onrush GUI looks when 2 processors are busy running frames.
The processors should free up fairly quickly, and onrush will subsequently show the processors become idle:
If you don't want to kill the rendering frames right away, choose 'offline'--
this will prevent new frames from starting while allowing the running
frames to complete.