Optimized the non blocking thread pool:

 * Use a pseudo-random permutation of queue indices during random stealing. This ensures that all the queues are considered.
 * Directly pop from a non-empty queue when we are waiting for work,
instead of first noticing that there is a non-empty queue and
then doing another round of random stealing to re-discover the non-empty
queue.
 * Steal only 1 task from a remote queue instead of half of tasks.

1 files changed, 8 insertions, 0 deletions

diff --git a/unsupported/test/cxx11_runqueue.cpp b/unsupported/test/cxx11_runqueue.cpp
index d20d87111..2594ff0c5 100644
--- a/unsupported/test/cxx11_runqueue.cpp
+++ b/unsupported/test/cxx11_runqueue.cpp
@@ -100,6 +100,14 @@ void test_basic_runqueue()
   // Empty again.
   VERIFY(q.Empty());
   VERIFY_IS_EQUAL(0u, q.Size());
+  VERIFY_IS_EQUAL(0, q.PushFront(1));
+  VERIFY_IS_EQUAL(0, q.PushFront(2));
+  VERIFY_IS_EQUAL(0, q.PushFront(3));
+  VERIFY_IS_EQUAL(1, q.PopBack());
+  VERIFY_IS_EQUAL(2, q.PopBack());
+  VERIFY_IS_EQUAL(3, q.PopBack());
+  VERIFY(q.Empty());
+  VERIFY_IS_EQUAL(0, q.Size());
 }
 
 // Empty tests that the queue is not claimed to be empty when is is in fact not.