1 files changed, 111 insertions, 0 deletions
diff --git a/dragon/benchmark.rb b/dragon/benchmark.rb
new file mode 100644
index 0000000..38ea991
--- /dev/null
+++ b/dragon/benchmark.rb
@@ -0,0 +1,111 @@
+# coding: utf-8
+# Copyright 2019 DragonRuby LLC
+# MIT License
+# benchmark.rb has been released under MIT (*only this file*).
+
+module GTK
+  class Runtime
+    module Benchmark
+      def benchmark_single iterations, name, proc
+        log <<-S
+** Invoking :#{name}...
+S
+        idx = 0
+        r = nil
+        time_start = Time.now
+        while idx < iterations
+          r = proc.call
+          idx += 1
+        end
+        result = (Time.now - time_start).round 3
+
+        { name: name,
+          time: result,
+          time_ms: (result * 1000).to_i }
+      end
+
+      def benchmark opts = {}
+        iterations = opts.iterations
+
+        log <<-S
+* BENCHMARK: Started
+** Caller: #{(caller || []).first}
+** Iterations: #{iterations}
+S
+        procs = opts.find_all { |k, v| v.respond_to? :call }
+
+        times = procs.map do |(name, proc)|
+          benchmark_single iterations, name, proc
+        end.sort_by { |r| r.time }
+
+        first_place = times.first
+        second_place = times.second || first_place
+
+        times = times.map do |candidate|
+          average_time = first_place.time
+                           .add(candidate.time)
+                           .abs
+                           .fdiv(2)
+
+          difference_percentage = 0
+          if average_time == 0
+            difference_percentage = 0
+          else
+            difference_percentage = first_place.time
+                                      .subtract(candidate.time)
+                                      .abs
+                                      .fdiv(average_time)
+                                      .imult(100)
+          end
+
+          difference_time = ((first_place.time - candidate.time) * 1000).round
+          candidate.merge(difference_percentage: difference_percentage,
+                          difference_time: difference_time)
+        end
+
+        too_small_to_measure = false
+        if (first_place.time + second_place.time) == 0
+          too_small_to_measure = true
+          difference_percentage = 0
+          log <<-S
+* BENCHMARK: Average time for experiments were too small. Increase the number of iterations.
+S
+        else
+          difference_percentage = (((first_place.time - second_place.time).abs.fdiv((first_place.time + second_place.time).abs.fdiv(2))) * 100).round
+        end
+
+        difference_time = first_place.time.-(second_place.time).*(1000).abs.round
+
+        r = {
+          iterations: iterations,
+          first_place: first_place,
+          second_place: second_place,
+          difference_time: difference_time,
+          difference_percentage: difference_percentage,
+          times: times,
+          too_small_to_measure: too_small_to_measure
+        }
+
+        log_message = []
+        only_one_result = first_place.name == second_place.name
+
+        if only_one_result
+          log <<-S
+* BENCHMARK: #{r.first_place.name} completed in #{r.first_place.time_ms}ms."
+S
+        else
+          log <<-S
+* BENCHMARK: #{r.message}
+** Fastest: #{r.first_place.name.inspect}
+** Second:  #{r.second_place.name.inspect}
+** Margin:  #{r.difference_percentage}% (#{r.difference_time.abs}ms) #{r.first_place.time_ms}ms vs #{r.second_place.time_ms}ms.
+** Times:
+#{r.times.map { |t| "*** #{t.name}: #{t.time_ms}ms (#{t.difference_percentage}% #{t.difference_time.abs}ms)." }.join("\n")}
+S
+        end
+
+        r
+      end
+    end
+  end
+end