Can't find info on this anywhere. Even just the scope would be useful: is it only stuff going on within the Houdini app, or could it be external processes (eg Safari, other apps running on the machine, OS overhead stuff)?
I'm running on a Mac, and I've Redshift installed too.
Trying to track down viewport performance issues in a big complex scene, and even with almost everything turned off, that “Unaccounted” process is eating a lot of cycles, it seems.
My guess would be unaccounted is any cycles that contributed to the cook but weren’t explicitly categorized by the book-keeping/trace mechanism used by Performance Monitor.