model: note the DPOR addendum

To prevent having problems with this in the future.

diff --git a/model.cc b/model.cc
index 6a79ad4a90f80ff1ee3177511683cd96c67ebb54..b93653becc41d7acf250d7ff1153490fad056d69 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -755,6 +755,7 @@ void ModelChecker::set_backtracking(ModelAction *act)
 
        Node *node = prev->get_node()->get_parent();
 
+       /* See Dynamic Partial Order Reduction (addendum), POPL '05 */
        int low_tid, high_tid;
        if (node->enabled_status(t->get_id()) == THREAD_ENABLED) {
                low_tid = id_to_int(act->get_tid());
@@ -771,6 +772,7 @@ void ModelChecker::set_backtracking(ModelAction *act)
                if (i >= node->get_num_threads())
                        break;
 
+               /* See Dynamic Partial Order Reduction (addendum), POPL '05 */
                /* Don't backtrack into a point where the thread is disabled or sleeping. */
                if (node->enabled_status(tid) != THREAD_ENABLED)
                        continue;