first of all, type this on your console or terminal
ps -ef | grep supervisord
You will get some pid of supervisord just like these
root 2641 12938 0 04:52 pts/1 00:00:00 grep --color=auto supervisord
root 29646 1 0 04:45 ? 00:00:00 /usr/bin/python /usr/local/bin/supervisord
if you get output like that, your pid is the second one. then if you want to shut down your supervisord you can do this
kill -s SIGTERM 29646
hope it helpful. ref: http://supervisord.org/running.html#signals