diff --git a/.gitignore b/.gitignore
index 75f473258..1a8c5990c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,9 @@
 *.bak
 *.d
 *.o
+/benchmark/**/*.dat
+/benchmark/*.pdf
+/benchmark/*.png
 *.orig
 *.pdb
 *.rej
diff --git a/Rakefile b/Rakefile
index fee43217c..66f54a4e2 100644
--- a/Rakefile
+++ b/Rakefile
@@ -29,6 +29,8 @@ load "#{MRUBY_ROOT}/tasks/libmruby.rake"
 load "#{MRUBY_ROOT}/tasks/mrbgems_test.rake"
 load "#{MRUBY_ROOT}/test/mrbtest.rake"
 
+load "#{MRUBY_ROOT}/tasks/benchmark.rake"
+
 ##############################
 # generic build targets, rules
 task :default => :all
diff --git a/benchmark/ao-render.rb b/benchmark/bm_ao_render.rb
similarity index 99%
rename from benchmark/ao-render.rb
rename to benchmark/bm_ao_render.rb
index 37bb4ad31..8212c3a13 100644
--- a/benchmark/ao-render.rb
+++ b/benchmark/bm_ao_render.rb
@@ -5,8 +5,8 @@
 # mruby version by Hideki Miura
 #
 
-IMAGE_WIDTH = 256
-IMAGE_HEIGHT = 256
+IMAGE_WIDTH = 64
+IMAGE_HEIGHT = 64
 NSUBSAMPLES = 2
 NAO_SAMPLES = 8
 
diff --git a/benchmark/fib39.rb b/benchmark/bm_fib.rb
similarity index 72%
rename from benchmark/fib39.rb
rename to benchmark/bm_fib.rb
index d5565b779..4b395f9cc 100644
--- a/benchmark/fib39.rb
+++ b/benchmark/bm_fib.rb
@@ -1,8 +1,7 @@
-# Fib 39
 
 def fib n
   return n if n < 2
   fib(n-2) + fib(n-1)
 end
 
-puts fib(39)
+puts fib(37)
diff --git a/benchmark/bm_so_lists.rb b/benchmark/bm_so_lists.rb
index f8d26797a..e8f4a2a5f 100644
--- a/benchmark/bm_so_lists.rb
+++ b/benchmark/bm_so_lists.rb
@@ -40,7 +40,7 @@ end
 
 i = 0
 while i<NUM
-  i+=1
+  i += 1
   result = test_lists()
 end
 
diff --git a/benchmark/build_config_boxing.rb b/benchmark/build_config_boxing.rb
new file mode 100644
index 000000000..b478c9005
--- /dev/null
+++ b/benchmark/build_config_boxing.rb
@@ -0,0 +1,28 @@
+MRuby::Build.new do |conf|
+  toolchain :gcc
+end
+
+MRuby::Build.new('no_boxing') do |conf|
+  toolchain :gcc
+
+  conf.gembox 'default'
+end
+
+MRuby::Build.new('word_boxing') do |conf|
+  toolchain :gcc
+
+  conf.gembox 'default'
+  conf.compilers.each do |c|
+    c.defines += %w(MRB_WORD_BOXING)
+  end
+end
+
+MRuby::Build.new('nan_boxing') do |conf|
+  toolchain :gcc
+
+  conf.gembox 'default'
+  conf.compilers.each do |c|
+    c.defines += %w(MRB_NAN_BOXING)
+  end
+end
+
diff --git a/benchmark/build_config_cc.rb b/benchmark/build_config_cc.rb
new file mode 100644
index 000000000..56d725bc7
--- /dev/null
+++ b/benchmark/build_config_cc.rb
@@ -0,0 +1,13 @@
+MRuby::Build.new do |conf|
+  toolchain :gcc
+end
+
+MRuby::Build.new('gcc') do |conf|
+  toolchain :gcc
+  conf.gembox 'default'
+end
+
+MRuby::Build.new('clang') do |conf|
+  toolchain :clang
+  conf.gembox 'default'
+end
diff --git a/benchmark/plot.gpl b/benchmark/plot.gpl
new file mode 100644
index 000000000..725e2ec1c
--- /dev/null
+++ b/benchmark/plot.gpl
@@ -0,0 +1,5 @@
+set yrange [0:]
+set terminal pngcairo font 'Sans, 8' lw 1 size 1400,1024
+set xtics rotate by -45
+set style histogram errorbars gap 2 lw 1
+set style fill solid border -1
diff --git a/tasks/benchmark.rake b/tasks/benchmark.rake
new file mode 100644
index 000000000..84e69ebee
--- /dev/null
+++ b/tasks/benchmark.rake
@@ -0,0 +1,91 @@
+module MRuby
+  BENCHMARK_REPEAT = 4
+end
+
+$dat_files = []
+
+def bm_files
+  Dir.glob("#{MRUBY_ROOT}/benchmark/bm_*.rb")
+end
+
+def build_config_name
+  if ENV['MRUBY_CONFIG']
+    File.basename(ENV['MRUBY_CONFIG'], '.rb').gsub('build_config_', '')
+  else
+    "build"
+  end
+end
+
+def plot_file
+  File.join(MRUBY_ROOT, 'benchmark', "#{build_config_name}.png")
+end
+
+def plot
+  opts_file = "#{MRUBY_ROOT}/benchmark/plot.gpl"
+  opts = File.read(opts_file).each_line.to_a.map(&:strip).join(';')
+
+  dat_files = $dat_files.group_by {|f| File.dirname(f).split(File::SEPARATOR)[-1]}
+
+  opts += ";set output '#{plot_file}'"
+
+  opts += ';plot '
+
+  opts += dat_files.keys.map do |data_file|
+    %Q['-' u 2:3:4:xtic(1) w hist title columnheader(1)]
+  end.join(',')
+  opts += ';'
+
+  cmd = %Q{gnuplot -p -e "#{opts}"}
+
+  IO.popen(cmd, 'w') do |p|
+    dat_files.each do |target_name, bm_files|
+      p.puts target_name.gsub('_', '-')
+      bm_files.each do |bm_file|
+        p.write File.read(bm_file)
+      end
+      p.puts "e"
+    end
+  end
+end
+
+
+MRuby.each_target do |target|
+  next if target.name == 'host'
+  mruby_bin = "#{target.build_dir}/bin/mruby"
+
+  bm_files.each do |bm_file|
+    bm_name = File.basename bm_file, ".rb"
+
+    dat_dir = File.join('benchmark', build_config_name, target.name)
+    dat_file = File.join(dat_dir, "#{bm_name}.dat")
+    $dat_files << dat_file
+
+    directory dat_dir
+
+    file dat_file => [bm_file, dat_dir, mruby_bin] do |task|
+      print bm_name
+      puts "..."
+
+      data = (0...MRuby::BENCHMARK_REPEAT).map do |n|
+        str = %x{(time -f "%e %S %U" #{mruby_bin} #{bm_file}) 2>&1 >/dev/null}
+        str.split(' ').map(&:to_f)
+      end
+
+      File.open(task.name, "w") do |f|
+        data = data.map {|_,r,s| (r + s) / 2.0}
+        min = data.min
+        max = data.max
+        avg = data.inject(&:+) / data.size
+        f.puts "#{bm_name.gsub('_', '-')} #{avg} #{min} #{max}"
+      end
+    end
+  end
+end
+
+file plot_file => $dat_files do
+  plot
+end
+
+task :benchmark => plot_file do
+  plot
+end
diff --git a/tasks/mruby_build.rake b/tasks/mruby_build.rake
index 8438b6ca4..66608286d 100644
--- a/tasks/mruby_build.rake
+++ b/tasks/mruby_build.rake
@@ -8,6 +8,7 @@ module MRuby
     end
 
     def each_target(&block)
+      return to_enum(:each_target) if block.nil?
       @targets.each do |key, target|
         target.instance_eval(&block)
       end