Comparison of Deadlock Recovery and Avoidance Mechanisms to Approach Message Dependent Deadlocks in On-chip Networks

With the transition from buses to on-chip networks in SoCs the problem of deadlocks in on-chip interconnects arises. Deadlocks can be caused by routing cycles in the network, or by message dependencies, even if the network itself is actually free of routing cycles. Two basic approaches to counter message dependent deadlocks exist: deadlock avoidance, which is most popular in NoCs, and deadlock recovery, which has until now only been used in parallel computer networks. Deadlock recovery promises low buffer space requirements and does not impose restrictions on connections between individual communication partners. For this study, we have adapted a deadlock recovery scheme for the use in NoCs and compared it to strict ordering as a representative of deadlock avoidance in terms of throughput and buffer space. The results show significant buffer space savings for deadlock recovery, however, at the cost of reduced data throughput.