Revert "Merge pull request #348 from y-yagi/use_available_processor_c…

…ount"

This reverts commit 21fdad7, reversing
changes made to 9644d13.

see #349

Readme.md

@@ -196,7 +196,6 @@ Tips
  - [Isolation] Do not reuse previous worker processes: `isolation: true`
  - [Stop all processes with an alternate interrupt signal] `'INT'` (from `ctrl+c`) is caught by default. Catch `'TERM'` (from `kill`) with `interrupt_signal: 'TERM'`
  - [Process count via ENV] `PARALLEL_PROCESSOR_COUNT=16` will use `16` instead of the number of processors detected. This is used to reconfigure a tool using `parallel` without inserting custom logic.
- - [Process count] `parallel` uses a number of processors seen by the OS for process count by default. If you want to use a value considering CPU quota, please add `concurrent-ruby` to your `Gemfile`.
 
 TODO
 ====

lib/parallel.rb

@@ -337,10 +337,10 @@ def physical_processor_count
       end
     end
 
-    # Number of processors seen by the OS or value considering CPU quota if the process is inside a cgroup,
-    # used for process scheduling
+    # Number of processors seen by the OS, used for process scheduling
     def processor_count
-      @processor_count ||= Integer(ENV['PARALLEL_PROCESSOR_COUNT'] || available_processor_count)
+      require 'etc'
+      @processor_count ||= Integer(ENV['PARALLEL_PROCESSOR_COUNT'] || Etc.nprocessors)
     end
 
     def worker_number
@@ -695,13 +695,5 @@ def instrument_start(item, index, options)
       return unless (on_start = options[:start])
       options[:mutex].synchronize { on_start.call(item, index) }
     end
-
-    def available_processor_count
-      require 'concurrent-ruby'
-      Concurrent.available_processor_count.floor
-    rescue LoadError, NoMethodError
-      require 'etc'
-      Etc.nprocessors
-    end
   end
 end

spec/parallel_spec.rb

@@ -49,6 +49,11 @@ def without_ractor_warning(out)
         (1..999).should include(Parallel.processor_count)
       end
     end
+
+    it 'uses Etc.nprocessors in Ruby 2.2+' do
+      defined?(Etc).should == "constant"
+      Etc.respond_to?(:nprocessors).should == true
+    end
   end
 
   describe ".physical_processor_count" do