Processing rate optimization by sequential system floorplanning

The performance of a sequential system is usually measured by its frequency. However, with the appearance of global interconnects that require multiple clock periods to communicate the throughput is usually traded-off for higher frequency (for example, through wire pipelining or latency insensitive design). Therefore, we propose to use the processing rate, defined as the amount of processed inputs per unit time, as the performance measure. We show that the minimal ratio of the flip-flop number over the delay on any cycle is an upper bound of the processing rate. Since the processing rate of a sequential system is mainly decided by its floorplan when interconnect delays are dominant, the problem of floorplanning for processing rate optimization is formulated and solved. We optimize the processing rate bound directly in a floorplanner by applying Howard's algorithm incrementally. Experimental results confirm the effectiveness of our approach.