SALSA: a new approach to scheduling with timing constraints

An approach to scheduling in high-level synthesis that meets timing constraints while attempting to minimize hardware resource costs is described. The approach is based on a modified control/data-flow graph (CDFG) representation called SALSA. SALSA provides a simple move set that allows alternative schedules to be quickly explored while maintaining timing constraints. It is shown that this move set is complete in that any legal schedule can be reached using some sequence of move applications. In addition, SALSA provides support for scheduling with conditionals, loops, and subroutines. Scheduling with SALSA is performed in two steps. First, an initial schedule that meets timing constraints is generated using a constraint solution algorithm adapted from layout compaction. Second, the schedule is improved using the SALSA move set under control of a simulated annealing algorithm. Results show the scheduler´s ability to find good schedules which meet timing constraints in reasonable execution times