On-line detection of the deadlocks caused by permanently faulty links in quasi-delay insensitive networks on chip

Asynchronous networks on chip (NoCs) are promising candidates for supporting the enormous communication needed by future many-core systems due to their low-energy and high-speed. Similar to synchronous NoCs, asynchronous NoCs are vulnerable to faults but their fault-tolerance is not studied adequately, especially the quasi-delay insensitive (QDI) NoCs. One of the key issues neglected by most designers is that permanent faults in QDI NoCs cause deadlocks, which cripples the traditional fault-tolerant techniques using redundant codes. A novel detection method has been proposed to locate the faulty link in a QDI NoC according to a common pattern shared by all fault-related deadlocks. It is shown that this method introduces low hardware overhead and reports permanently faulty links with a short delay and guaranteed accuracy.