PLS: a scheduler for pipeline synthesis

The authors point out that pipelining is an effective method for optimizing the execution of a loop, especially for digital signal processing (DSP) applications where data enter a circuit regularly. Although throughput and turnaround time are two important optimization criteria, previous work emphasized mainly the throughput. It is shown that the delay time for executing an iteration of a loop has a strong relationship to the cost of the registers and the controller. By minimizing the delay, there is more silicon area to allocate to additional resources, which in turn increases throughput. Forward scheduling and a backward scheduling are iteratively used to achieve this purpose. The algorithm, called PipeLining Scheduler or PLS, can be used to pipeline a loop with or without loop-carried dependencies. Real examples are used to illustrate the method. Experiments on benchmark examples show that considerable improvement over previous approaches is attained