The Practical Application of Retiming to the Design of High-Performance Systems

Many advances have been made recently in the theory of circuit retiming, especially for circuits that use level-sensitive latches. In spite of this, automatic retiming tools have seen relatively little use in practice. One reason for this is the lack of good speedup results when retiming has been applied to real circuits. Another reason is that retiming has used a rather simple circuit model which reduces its utility in practice. This paper addresses both of these issues. We suggest that the reason for the poor results reported for retiming is that retiming has been applied too late in the design process when there is little flexibility for performance improvement. We give an example of using retiming early in the design process to achieve better performance while at the same time simplifying the design process itself. We then describe an extension to the retiming circuit model that includes clock skew as well as latch propagation delay, setup and hold parameters. Including these param..