Used https://github.com/dakull/ruby-simple-benchmarks/ for benchmarking
> ruby --version
ruby 2.1.0p0 (2013-12-25 revision 44422) [x86_64-linux]
> time ruby bm_gc_mb.rb
user system total real
0.200000 0.010000 0.210000 ( 0.208676)
0.300000 0.020000 0.320000 ( 0.323699)
1.000000 0.070000 1.070000 ( 1.064552)
ruby bm_gc_mb.rb 1,56s user 0,14s system 88% cpu 1,918 total
> time ruby bm_gc_string.rb
user system total real
3.360000 0.090000 3.450000 ( 3.455224)
7.250000 0.040000 7.290000 ( 7.297208)
10.130000 0.030000 10.160000 ( 10.156744)
ruby bm_gc_string.rb 20,78s user 0,19s system 99% cpu 20,979 total
> time ruby for_vs_each.rb
user system total real
0.290000 0.000000 0.290000 ( 0.287766)
0.260000 0.000000 0.260000 ( 0.256716)
ruby for_vs_each.rb 0,60s user 0,00s system 78% cpu 0,766 total
> time ruby good_to_know.rb
user system total real
0.060000 0.000000 0.060000 ( 0.067809)
0.250000 0.010000 0.260000 ( 0.246962)
ruby good_to_know.rb 0,36s user 0,01s system 99% cpu 0,369 total
> ruby --version
ruby 2.1.1p76 (2014-02-24 revision 45161) [x86_64-linux]
> time ruby bm_gc_mb.rb
user system total real
0.180000 0.030000 0.210000 ( 0.205150)
0.310000 0.000000 0.310000 ( 0.312566)
1.010000 0.040000 1.050000 ( 1.057199)
ruby bm_gc_mb.rb 1,57s user 0,11s system 99% cpu 1,674 total
> time ruby bm_gc_string.rb
user system total real
3.510000 0.050000 3.560000 ( 3.574144)
7.010000 0.090000 7.100000 ( 7.099202)
10.950000 0.050000 11.000000 ( 11.001718)
ruby bm_gc_string.rb 21,53s user 0,22s system 99% cpu 21,751 total
> time ruby for_vs_each.rb
user system total real
0.270000 0.000000 0.270000 ( 0.268384)
0.260000 0.000000 0.260000 ( 0.256476)
ruby for_vs_each.rb 0,58s user 0,00s system 99% cpu 0,585 total
> time ruby good_to_know.rb
user system total real
0.060000 0.000000 0.060000 ( 0.064042)
0.250000 0.010000 0.260000 ( 0.246753)
ruby good_to_know.rb 0,36s user 0,01s system 99% cpu 0,370 total