Reconfigurable processor architectures exploiting high bandwidth optical channels

There is growing interest in studying the possibility of reconfigurable architectures as replacements for general purpose computing for certain application domains. Reconfigurable systems can take advantage of deep computational pipelines, perform concurrent execution and are inherently data flow in nature. Furthermore, these systems have the capability of 'on the fly' reconfiguration of all or portions of the hardware to represent all the functionality required to complete the execution of an application. However, these architectures suffer from slow run time reconfiguration (RTR) due to the fact that the configuration memory resides off-chip and hence requires high access latency. This disadvantage limits the system performance and the application domain in which reconfigurable systems could prove effective. To overcome slow RTR, recent approaches include on-chip configuration memory to cache the next possible configurations. This approach trades off die area for fast RTR which diminishes the processing power of the reconfigurable processor. The high cost of adding configuration cache, up to 50% of the die area, would considerably increase the number of hardware reconfigurations required compared to architectures without on-chip cache. This paper presents an alternative reconfigurable architecture which overcomes these limitations by exploiting high bandwidth optical channels. We develop a performance model to analyze and compare the performance of cache based RTR architectures, optical based RTR architectures and hybrid optical-cache based RTR architectures.