Optimizing the overhead for network-on-chip routing reconfiguration in parallel multi-core platforms

Abstract

In order to cope with an increased level of resource contention and dynamic application behaviour, the runtime reconfiguration of the routing function of an on-chip interconnection network is a desirable feature for multi-core hardware platforms in the embedded computing domain. The most intuitive approach consists of draining the network from ongoing packets before reconfiguring its routing tables, thus preventing the occurrence of deadlock from the ground up. The impact on application performance is however unacceptable. On the other hand, truly dynamic approaches are too much of an overhead for an on-chip setting. Recently, the overlapped static reconfiguration (OSR) method was proven to be capable of routing reconfiguration in the presence of background traffic with only a mild impact on the resource budget. This work finds that this method is still far from materializing its potentials in terms of reconfiguration performance (both impact on background traffic, which is still there to some extent, and duration of the reconfiguration transient). Therefore, it proposes a set of optimization methods for OSR spanning the trade-off between performance improvements and implementation cost. To the limit, fully transparent reconfiguration is delivered.