If I run GNU time with some large program, I get the following output:
604.90user 13.16system 11:05.56elapsed 92%CPU (0avgtext+0avgdata 0maxresident)k
712inputs+0outputs (5major+76648minor)pagefaults 0swaps

Question - I would guess that maxresident would refer to maximum resident memory usage of the program that I ran, but why is it always zero?