Benchmark making regexps.

bench.rb

require 'benchmark'

STRING = "string"
def sm ; STRING  ; end
def sl ; "string" ; end

Benchmark.bmbm do |x|
  t = 10_000_000
  x.report("string-constant") { t.times { STRING } }
  x.report("string-literal") { t.times { "string" } }
  x.report("regexp-literal") { t.times { /string/ } }
  x.report("regexp-inter-string-constant") { t.times { /#{STRING}/ } }
  x.report("regexp-inter-string-constant-m") { t.times { /#{sm}/ } }
  x.report("regexp-inter-string-literal") { t.times { /#{"string"}/ } }
  x.report("regexp-inter-string-literal-m") { t.times { /#{sl}/ } }
end

results-jruby-1.7-on-jvm-1.6.txt

Rehearsal ------------------------------------------------------------------
string-constant                  1.710000   0.140000   1.850000 (  1.070000)
string-literal                   1.070000   0.020000   1.090000 (  1.030000)
regexp-literal                   0.670000   0.000000   0.670000 (  0.648000)
regexp-inter-string-constant     7.600000   0.040000   7.640000 (  7.516000)
regexp-inter-string-constant-m   8.260000   0.030000   8.290000 (  8.221000)
regexp-inter-string-literal      0.680000   0.000000   0.680000 (  0.672000)
regexp-inter-string-literal-m    8.360000   0.020000   8.380000 (  8.408000)
-------------------------------------------------------- total: 28.600000sec

                                     user     system      total        real
string-constant                  0.640000   0.000000   0.640000 (  0.649000)
string-literal                   0.920000   0.000000   0.920000 (  0.912000)
regexp-literal                   0.650000   0.000000   0.650000 (  0.647000)
regexp-inter-string-constant     7.580000   0.020000   7.600000 (  7.619000)
regexp-inter-string-constant-m   8.120000   0.030000   8.150000 (  8.152000)
regexp-inter-string-literal      0.680000   0.000000   0.680000 (  0.682000)
regexp-inter-string-literal-m    8.130000   0.010000   8.140000 (  8.140000)

results-mri-1.9.3-p327-patch-falcon-gc.txt

Rehearsal ------------------------------------------------------------------
string-constant                  0.780000   0.000000   0.780000 (  0.772820)
string-literal                   1.740000   0.000000   1.740000 (  1.745241)
regexp-literal                   0.740000   0.000000   0.740000 (  0.745060)
regexp-inter-string-constant    37.140000   0.000000  37.140000 ( 37.178668)
regexp-inter-string-constant-m  38.300000   0.030000  38.330000 ( 38.419389)
regexp-inter-string-literal      0.740000   0.000000   0.740000 (  0.743964)
regexp-inter-string-literal-m   40.250000   0.010000  40.260000 ( 40.296169)
------------------------------------------------------- total: 119.730000sec

                                     user     system      total        real
string-constant                  0.720000   0.000000   0.720000 (  0.724254)
string-literal                   1.700000   0.000000   1.700000 (  1.700508)
regexp-literal                   0.700000   0.000000   0.700000 (  0.701369)
regexp-inter-string-constant    37.100000   0.000000  37.100000 ( 37.135231)
regexp-inter-string-constant-m  38.320000   0.000000  38.320000 ( 38.400480)
regexp-inter-string-literal      0.700000   0.000000   0.700000 (  0.702838)
regexp-inter-string-literal-m   40.000000   0.000000  40.000000 ( 40.038571)