Exploring performance tradeoffs for clustered VLIW ASIPs

VLIW ASIPs provide an attractive solution for increasingly pervasive real-time multimedia and signal processing embedded applications. In this paper we propose an algorithm to support trade-off exploration during the early phases of the design/specialization of VLIW ASIPs with clustered datapaths. For purposes of an early exploration step, we define a parameterized family of clustered datapaths D(m,n), where m and n denote interconnect capacity and cluster capacity constraints on the family. Given a kernel, the proposed algorithm explores the space of feasible clustered datapaths and returns: a datapath configuration; a binding and scheduling for the operations; and a corresponding estimate for the best achievable latency over the specified family. Moreover, we show how the parameters m and n, as well as a target latency optionally specified by the designer, can be used to effectively explore trade-offs among delay, power/energy, and latency. Extensive empirical evidence is provided showing that the proposed approach is strikingly effective at attacking this complex optimization problem.