Benchmark: running comp, space, each for at least 3 CPU seconds...
      comp:  4 wallclock secs ( 3.03 usr +  0.01 sys =  3.04 CPU) @ 898773.68/s (n=2732272)
     space:  5 wallclock secs ( 3.12 usr + -0.02 sys =  3.10 CPU) @ 795990.97/s (n=2467572)