1 files changed, 51 insertions, 0 deletions
diff --git a/test/thread/lbtest.rb b/test/thread/lbtest.rb
new file mode 100755
index 0000000000..10bb90185f
--- /dev/null
+++ b/test/thread/lbtest.rb
@@ -0,0 +1,51 @@
+#! /usr/bin/ruby
+require 'thread'
+
+class LocalBarrier
+  def initialize(n)
+    @wait = Queue.new
+    @done = Queue.new
+    @keeper = begin_keeper(n)
+  end
+
+  def sync
+    @done.push(true)
+    @wait.pop
+  end
+
+  def join
+    @keeper.join
+  end
+
+  private
+  def begin_keeper(n)
+    Thread.start do
+      n.times do
+        @done.pop
+      end
+      n.times do
+        @wait.push(true)
+      end
+    end
+  end
+end
+
+n = 10
+
+lb = LocalBarrier.new(n)
+
+(n - 1).times do |i|
+  Thread.start do
+    sleep((rand(n) + 1) / 10.0)
+    puts "#{i}: done"
+    lb.sync
+    puts "#{i}: cont"
+  end
+end
+
+lb.sync
+puts "#{n-1}: done"
+
+# lb.join # leaving waiting threads.
+
+puts "exit."