+ *
+ * broadcast_rarp shares a cacheline in the virtio_net structure
+ * with some fields that are accessed during enqueue and
+ * rte_atomic16_cmpset() causes a write if using cmpxchg. This could
+ * result in false sharing between enqueue and dequeue.
+ *
+ * Prevent unnecessary false sharing by reading broadcast_rarp first
+ * and only performing cmpset if the read indicates it is likely to
+ * be set.