cpu time (using time()), wall clock (using time command)
size: 10,000
             cpu time  wall clock
bubble:      11.26     11.75 11.324u 0.039s 0:11.75 96.5% 0+0k 400+8io 3pf+0w
bubbleopt:   11.57     11.79 11.647u 0.038s 0:11.79 98.9% 0+0k 0+8io 1pf+0w
selection:   5.21      5.29  5.291u 0.035s 0:05.53 96.2%  0+0k 0+8io 1pf+0w
insertion:   6.26      6.35  6.351u 0.029s 0:06.50 98.0%  0+0k 0+8io 1pf+0w
mergesort:   0.075     0.16  0.161u 0.036s 0:00.43 44.1%  0+0k 0+8io 1pf+0w
quicksort:   0.055     0.13  0.132u 0.034s 0:00.25 64.0%  0+0k 0+8io 1pf+0w
radixsort:   0.019     0.097 0.097u 0.022s 0:00.16 68.7%  0+0k 0+0io 0pf+0w

size: 500,000 (for O(n log n) algorithms or better only)
             cpu time  wall clock
mergesort:   5.13      6.08 6.081u 0.051s 0:06.18 99.1%	0+0k 0+8io 1pf+0w
quicksort:   3.85      4.81 4.812u 0.036s 0:05.00 96.8%	0+0k 0+8io 1pf+0w
radixsort:   1.55      2.55 2.549u 0.028s 0:02.66 96.2%	0+0k 0+0io 0pf+0w