--- old/src/share/vm/gc/g1/g1CollectionSet.cpp	2016-09-08 10:52:21.493370864 +0200
+++ new/src/share/vm/gc/g1/g1CollectionSet.cpp	2016-09-08 10:52:21.351366469 +0200
@@ -396,6 +396,17 @@
   return time_remaining_ms;
 }
 
+static int compare_region_idx(const void *a, const void*b) {
+  uint const first = *(uint*)a;
+  uint const second = *(uint*)b;
+  assert(first != second, "Two regions with the same index %u in the collection set", first);
+  if (first > second) {
+    return 1;
+  } else {
+    return -1;
+  }
+}
+
 void G1CollectionSet::finalize_old_part(double time_remaining_ms) {
   double non_young_start_time_sec = os::elapsedTime();
   double predicted_old_time_ms = 0.0;
@@ -493,6 +504,8 @@
 
   double non_young_end_time_sec = os::elapsedTime();
   phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
+
+  qsort(_collection_set_regions, _collection_set_cur_length, sizeof(uint), compare_region_idx);
 }
 
 #ifdef ASSERT