stopwatch: Add latch_poll to stopwatch loop.
Nothing was clearing the latch, so the loop was busy. This makes it so
the loop only runs on new calls to latch_set() by a separate thread.
@@ -429,6 +429,7 @@ stopwatch_thread(void *ign OVS_UNUSED)
struct ovs_list command_list;
struct stopwatch_packet *pkt;
+ latch_poll(&stopwatch_latch);
guarded_list_pop_all(&stopwatch_commands, &command_list);
ovs_mutex_lock(&stopwatches_lock);
LIST_FOR_EACH_POP (pkt, list_node, &command_list) {
