chore: add a rake task to measure performance of each version

Rakefile

@@ -22,6 +22,17 @@ namespace :benchmark do
     load File.expand_path("../benchmark/pure.rb", __FILE__)
     puts
   end
+
+  task :measure do
+    tags = ENV['TAGS'] ? ENV['TAGS'].split(',') : `git tag --list`.split.select { |v| v.match? /\Av1\.[1-9]\.\d\z/ }
+    puts 'version,label,utime,stime,cutime,cstime,real'
+    tags.each do |tag|
+      sh("git checkout -f #{tag} 1>&2")
+      sh('git checkout master -- benchmark 1>&2')
+      sh('bundle exec rake clobber compile 1>&2')
+      sh("ruby #{File.expand_path("../benchmark/measure.rb", __FILE__)}")
+    end
+  end
 end
 
 task compare: :compile do

benchmark/measure.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require File.expand_path('../env', __FILE__)
+require 'jaro_winkler'
+require 'benchmark'
+require 'csv'
+
+csv = CSV.new($stdout)
+n = 100_000
+
+jobs = case JaroWinkler::VERSION
+when /\A1\.1/
+  {
+    ascii: -> { n.times { SAMPLES[:ascii].each { |str1, str2| JaroWinkler.c_distance(str1, str2) } } }
+  }
+when /\A1\.[2-3]/
+  {
+    ascii: -> { n.times { SAMPLES[:ascii].each { |str1, str2| JaroWinkler.c_distance(str1, str2) } } },
+    utf8: -> { n.times { SAMPLES[:utf8].each { |str1, str2| JaroWinkler.c_distance(str1, str2) } } }
+  }
+else
+  {
+    ascii: -> { n.times { SAMPLES[:ascii].each { |str1, str2| JaroWinkler.distance(str1, str2) } } },
+    utf8: -> { n.times { SAMPLES[:utf8].each { |str1, str2| JaroWinkler.distance(str1, str2) } } }
+  }
+end
+
+# rehearsal
+
+jobs.each { |label, job| Benchmark.measure(label, &job) }
+
+# take
+
+jobs.each do |label, job|
+  GC.start
+  tms = Benchmark.measure(label, &job)
+  # version,label,utime,stime,cutime,cstime,real
+  csv << [JaroWinkler::VERSION, *tms.to_a]
+end