CSTEP Resource Constraints

The Control Step Scheduler (CSTEP) schedules the behavioral operations into control steps, determining the parallelism of the design. It considers the structural partitions suggested by the Architectural Partitioning tool as well as timing and resource constraints specified by the designer. 

This chapter has described the design and implementation of CSTEP, the Workbench scheduling tool. CSTEP was designed for speed and flexibility and supports scheduling with resource constraints and interface timing constraints. 

The CSTEP control step scheduler uses list scheduling on a block-by-block basis, with timing constraint evaluation as the priority function. Operations are scheduled into control steps one basic block at a time, with the blocks scheduled in executidepth-first traversal of the control flow graph. For each basic block, data ready operator are considered for placement into the current control step, using a priority function that reflects whether or not that placement will violate timing constraints. Resource limits may be applied to limit the number of operators of a particular type in any one control step. 

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