bench_constant_vs_literal_hash_keys.rb

require "benchmark"

KEY = '1234567890'

HASH = {
  KEY => KEY
}

TESTS = 2_000_000

desc = defined?(RUBY_DESCRIPTION) ? RUBY_DESCRIPTION : "#{RUBY_ENGINE} #{JRUBY_VERSION} #{RUBY_PLATFORM} #{RUBY_VERSION}-#{RUBY_PATCHLEVEL} #{RUBY_RELEASE_DATE}"
puts "#{TESTS} iterations on #{desc}"

Benchmark.bmbm do |results|
  results.report("null:") { TESTS.times {  } }
  results.report("literal:") { TESTS.times { HASH['1234567890'] } }
  results.report("constant:") { TESTS.times { HASH[KEY] } }
end

# 2000000 iterations on ruby 1.8.7 (2009-06-12 patchlevel 174) [i686-darwin9]
# Rehearsal ---------------------------------------------
# null:       0.170000   0.000000   0.170000 (  0.167186)
# literal:    0.970000   0.000000   0.970000 (  0.973287)
# constant:   0.820000   0.010000   0.830000 (  0.829517)
# ------------------------------------ total: 1.970000sec
# 
#                 user     system      total        real
# null:       0.160000   0.000000   0.160000 (  0.164504)
# literal:    0.970000   0.000000   0.970000 (  0.981910)
# constant:   0.820000   0.000000   0.820000 (  0.825384)

# 2000000 iterations on ruby 1.9.1p0 (2009-01-30 revision 21907) [i386-darwin9]
# Rehearsal ---------------------------------------------
# null:       0.220000   0.000000   0.220000 (  0.225207)
# literal:    0.800000   0.010000   0.810000 (  0.803873)
# constant:   0.560000   0.000000   0.560000 (  0.562713)
# ------------------------------------ total: 1.590000sec
# 
#                 user     system      total        real
# null:       0.230000   0.000000   0.230000 (  0.226002)
# literal:    0.790000   0.000000   0.790000 (  0.800224)
# constant:   0.560000   0.000000   0.560000 (  0.558704)


# 2000000 iterations on jruby 1.3.0 java 1.8.6-287 2009-06-03
# Rehearsal ---------------------------------------------
# null:       0.246000   0.000000   0.246000 (  0.171000)
# literal:    0.593000   0.000000   0.593000 (  0.593000)
# constant:   0.292000   0.000000   0.292000 (  0.293000)
# ------------------------------------ total: 1.131000sec
# 
#                 user     system      total        real
# null:       0.097000   0.000000   0.097000 (  0.097000)
# literal:    0.389000   0.000000   0.389000 (  0.389000)
# constant:   0.316000   0.000000   0.316000 (  0.316000)