rake/cpu_counter.rb: use Etc.nprocessors

* lib/rake/cpu_counter.rb (count): prefer Etc.nprocessors, which
  is hundreds times faster.

* test/rake/test_rake_cpu_counter.rb: add tests for features, and
  remove useless tests.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48127 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/rake/cpu_counter.rb b/lib/rake/cpu_counter.rb
index d7c92a6cbe..6d0b878b19 100644
--- a/lib/rake/cpu_counter.rb
+++ b/lib/rake/cpu_counter.rb
@@ -44,6 +44,18 @@ module Rake
       end
     end
 
+    begin
+      require 'etc'
+    rescue LoadError
+    else
+      if Etc.respond_to?(:nprocessors)
+        undef count
+        def count
+          return Etc.nprocessors
+        end
+      end
+    end
+
     def count_via_java_runtime
       Java::Java.lang.Runtime.getRuntime.availableProcessors
     rescue StandardError