"pstack" is a workalike for the Solaris program of the same name.
Running pstack on a process produces a stack trace of
each thread in that process.

It's useful for finding out what wedged processes are up to, getting
profiles of applications, and just satisfying one's curiosity.

WWW: https://www.kib.kiev.ua/git/gitweb.cgi?p=pstacku.git;a=tree