Reconfiguration Management

This chapter discusses a variety of methods proposed and used to reduce and in some cases to remove reconfiguration overhead, including various configuration architecture designs, scheduling, and caching techniques, and ways to reduce the configuration data size. The difficulty of clock speed increases and power consumption concerns motivate reconfigurable computing as an important technique to advance digital design, implementing compute-intensive application tasks in reconfigurable hardware. However, the performance and power penalty of reconfiguration has the real potential to overwhelm its benefits. In many cases, several approaches can be combined to further reduce the overhead. For example, relocation and defragmentation architectural features facilitate advanced configuration scheduling mechanisms that load configurations in advance of their use to minimize processor stall time during reconfiguration. Likewise, a configuration cache can be combined with a relocation- and defragmentation-enabled design that uses a staging area, providing a wide path to configuration memory to decrease transfer time. This in turn can be combined with wildcarding to allow multiple identical rows or columns to be configured simultaneously. Such combined methods allow reconfigurable computing system designers to effectively minimize reconfiguration overhead and to provide the full benefit of reconfigurable computing in future computing systems.