test/threads: Fix hang opal_condition.c

Simplify the loop to get rid of the i, add a
signal at the end to ensure the other thread
can perform the last increment, and not hang
waiting.

Signed-off-by: Austen Lauria <awlauria@us.ibm.com>
(cherry picked from commit 736e244)

Author: awlauria

test/threads/opal_condition.c

@@ -42,40 +42,47 @@ static volatile int thr2_count = 0;
 
 static void* thr1_run(opal_object_t* obj)
 {
-    int i;
     clock_t c1, c2;
-    opal_mutex_lock(&mutex);
     c1 = clock();
-    for(i=0; i<TEST_COUNT; i++) {
-        opal_condition_wait(&thr1_cond, &mutex);
-        opal_condition_signal(&thr2_cond);
+    opal_mutex_lock(&mutex);
+    while (TEST_COUNT != thr1_count) {
         thr1_count++;
+        opal_condition_signal(&thr2_cond);
+        opal_condition_wait(&thr1_cond, &mutex);
     }
-    c2 = clock();
+
+    // Whoever gets here first needs to alert the other
+    // thread for their last iteration.
+    opal_condition_signal(&thr2_cond);
     opal_mutex_unlock(&mutex);
-    fprintf(stderr, "thr1: time per iteration: %ld usec\n", (long)((c2 - c1) / TEST_COUNT));
+    c2 = clock();
+    fprintf(stderr, "thr1: time per iteration: %ld uses\n", (long)((c2 - c1) / TEST_COUNT));
     return NULL;
 }
 
 static void* thr2_run(opal_object_t* obj)
 {
-    int i;
     clock_t c1, c2;
-    opal_mutex_lock(&mutex);
     c1 = clock();
-    for(i=0; i<TEST_COUNT; i++) {
+    opal_mutex_lock(&mutex);
+    while(TEST_COUNT != thr2_count) {
+        thr2_count++;
         opal_condition_signal(&thr1_cond);
         opal_condition_wait(&thr2_cond, &mutex);
-        thr2_count++;
     }
-    c2 = clock();
+
+    // Whoever gets here first needs to alert the other
+    // thread for the last iteration.
+    opal_condition_signal(&thr1_cond);
     opal_mutex_unlock(&mutex);
+
+    c2 = clock();
     fprintf(stderr, "thr2: time per iteration: %ld usec\n", (long)((c2 - c1) / TEST_COUNT));
     return NULL;
 }
 
 
-int main(int argc, char** argv)
+int main(int argc, char **argv)
 {
     int rc;
     opal_thread_t* thr1;