I ran only top, not htop. I did stop rngd, but no noticeable change occurred. After logging out and back in, whatever it was, was still running.
Since top did not show a busy process, the load average was 0.41, and the color was red, I assume it was something in the kernel?
One screenshot shows 1 running process, top, and another shows 2 running processes, and the other was pool-gnome-shel. But something is wrong in the kernel, since the process tree is not showing anyone busy, and the cpu is not charged to a process. It has to be down in the kernel. I am not a kernel guy, although, perhaps it is time to start! It took rebooting for the problem to go away.
I thought this was interesting, but it is not from the problem system:
dmesg | grep \-22
[ 1.688890] nouveau 0000:01:00.0: DRM: failed to create kernel channel, -22