Benchmark: timing 100000 iterations ... alternation, grouping: 12 wallclock secs (11.92 usr + 0.00 sys = 11.92 CPU) @ 8389.26/s (n=100000) alternation, no grouping: 0 wallclock secs ( 0.19 usr + 0.00 sys = 0.19 CPU) @ 526315.79/s (n=100000) (warning: too few iterations for a reliable count) loop, grouping: 2 wallclock secs ( 1.33 usr + 0.00 sys = 1.33 CPU) @ 75187.97/s (n=100000) loop, no grouping: 1 wallclock secs ( 1.33 usr + 0.00 sys = 1.33 CPU) @ 75187.97/s (n=100000)