What do the statistics (usr, sys, cusr, csys, and CPU) outputted by Perl's prove command mean?

Question

I've done quite a bit of Googling but can't find an answer to this question. When you run prove on your tests (http://perldoc.perl.org/prove.html), you get some statistics that look like:

Files=3, Tests=45,  2 wallclock secs ( 0.03 usr  0.00 sys +  0.50 cusr  0.12 csys =  0.65 CPU)

What do the numbers given for usr, sys, cusr, csys and CPU mean?

Answer 1

Wallclock seconds is the actual elapsed time, as if you looked at your watch to time it.

The usr seconds in the time actually spent on the CPU, in user space.

The sys seconds is the time actually spent on the CPU, in kernel space.

The CPU time is the total time spent on the CPU.

I don't know what cusr and csys represents, I guess they mean children_user and children_system?