From e385d78b2955940051edf1eff874d14666b1a14d Mon Sep 17 00:00:00 2001
From: Sameer Kumar <sameerk@us.ibm.com>
Date: Tue, 26 Feb 2013 09:49:24 +0000
Subject: [PATCH] BGQ: Adding blocking atomic queue

---
 src/arch/pami-bluegeneq/L2AtomicQueue.h | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/arch/pami-bluegeneq/L2AtomicQueue.h b/src/arch/pami-bluegeneq/L2AtomicQueue.h
index d6e7f8ec0d..d1db471134 100644
--- a/src/arch/pami-bluegeneq/L2AtomicQueue.h
+++ b/src/arch/pami-bluegeneq/L2AtomicQueue.h
@@ -18,6 +18,8 @@
 #define L2A_EAGAIN  -1
 #define L2A_FAIL    -2
 
+#define __L2_ATOMIC_QUEUE_BLOCKING  1
+
 typedef  void* L2AtomicQueueElement;
 
 typedef struct _l2atomicstate {
@@ -105,10 +107,13 @@ void * L2AtomicDequeue (L2AtomicQueue    *queue)
   volatile void *e = NULL;
   if (head < tail) {    
     e = queue->_array[head & qsize_1];
+#if __L2_ATOMIC_QUEUE_BLOCKING
     while (e == NULL) 
       e = queue->_array[head & qsize_1];
-
-    //fprintf(stderr,"Found message %p\n", e);
+#else
+    if (e == NULL)
+      return NULL;
+#endif
 
     queue->_array[head & qsize_1] = NULL;
     ppc_msync();
-- 
2.11.4.GIT