* benchmark/driver.rb: Add difference column to report that averages

	  across all runs of a benchmark.  [Ruby 1.9 - Feature #4982]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@32430 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 20 insertions, 1 deletions

diff --git a/benchmark/driver.rb b/benchmark/driver.rb
index c38c4fb3da..7dab292a15 100644
--- a/benchmark/driver.rb
+++ b/benchmark/driver.rb
@@ -90,6 +90,10 @@ class BenchmarkDriver
     end
   end
 
+  def average results
+    results.inject(:+) / results.length
+  end
+
   def show_results
     output
 
@@ -109,7 +113,10 @@ class BenchmarkDriver
       output "minimum results in each #{@repeat} measurements."
     end
 
-    output "name\t#{@execs.map{|(e, v)| v}.join("\t")}"
+    difference = "\taverage difference" if @execs.length == 2
+    total_difference = 0
+
+    output "name\t#{@execs.map{|(e, v)| v}.join("\t")}#{difference}"
     @results.each{|v, result|
       rets = []
       s = nil
@@ -129,8 +136,20 @@ class BenchmarkDriver
         end
         rets << sprintf("%.3f", r)
       }
+
+      if difference
+        diff = average(result.last) - average(result.first)
+        total_difference += diff
+        rets << sprintf("%.3f", diff)
+      end
+
       output "#{v}#{s}\t#{rets.join("\t")}"
     }
+
+    if difference and @verbose
+      output '-----------------------------------------------------------'
+      output "average total difference is #{total_difference}"
+    end
   end
 
   def files