Explicitly Staged Software Pipelining

Abstract

<p> Software Pipelining is a method of instruction scheduling where loops are scheduled more efficiently by executing operations from more than one iteration of the loop in parallel. Finding an optimal software pipelined schedule is NP-complete, but many heuristic algorithms exist. </p> In iteration i, a software pipelined loop will execute, in parallel, "stage" 1 of iteration i, stage 2 of iteration i- 1 and so on until stage k of iteration i-k+l. </p> <p> We present a new approach to software pipelining based on using a hemistic algorithm to explicitly assign each operation to its stage before the actual scheduling. </p> <p> This explicit assignment allows us to implement control flow mechanisms that are hard to implement with traditional methods of software pipelining, which do not give us direct control over what stages instructions are assigned to. </p>