Scheduling for optimum data memory compaction in block diagram oriented software synthesis

Abstract

For the design of complex digital signal processing systems, block diagram oriented synthesis of real time software for programmable target processors has become an important design aid. The synthesis approach discussed in this paper is based on multirate block diagrams with scalable synchronous data ow (SSDF) semantics. For this class of data ow graphs we present s c heduling techniques for optimum data memory compaction. These techniques can be employed to map signals of a block diagram onto a minimum data memory space. In order to formalize the data memory compaction problem, we rst derive appropriate implementation measures. Based on these implementation measures it can be shown that optimum data memory compaction consists of optimum scheduling as well as optimum memory allocation. For the class of single appearance (SA) block diagrams with SSDF semantics, scheduling can be reduced to an integer linear programming (ILP) problem. Due to the computational complexity of ILP, w e also present a suboptimum scheduling selection criterion, which can be used for SA and non SA-schedulers.

Static Rate-Optimal Scheduling of Multirate DSP Algorithms via Retiming and Unfolding

“…The first set of SDFGs consists of five practical DSP applications, including a sample rate converter (SaRate) [20], a satellite receiver (Satellite) [3], a maximum entropy spectrum analyzer (MaxES) (http://ptolemy.eecs.berkeley.edu/), an Mp3 playback application (Mp3) (http://www.es.ele.tue.nl/sdf3/) and a channel equalizer (CEer) [21]. Adopting the method in [2], by introducing to each model a dummy actor with computation time zero and edges with proper rates and delays to connect the dummy actor to the actors that have no incoming edges or no outgoing edges, we convert these models to strongly connected graphs.…”

“…The sample rate converter [20] MaxES The maximum entropy spectrum analyzer CEer The channel equalizer [21] Satellite The satellite receiver [3] B. Experimental Results Table II gives the information about and results for the practical DSP examples.…”

“…Each node (also called actor) in an SDFG represents a computation or function and each edge models a FIFO channel; the sample rates of actors may differ. Practical multirate DSP applications modeled with SDFGs include a spectrum analyzer [2], a satellite receiver [3], etc.…”

The CBP Parameter: A Module Characterization Approach for DSP Software Optimization

“…We have also given general, tight expressions for the CBP parameters of a number of additional practical DSP building blocks, which were obtained by analyzing implementations in the DSP libraries provided within the Ptolemy design environment [32]. Useful directions for further study include investigating tools to help automate the derivation of tight CBP parameters; integrating CBP-based buffering analysis, multidimensional dataflow modeling [34], and cyclo-static dataflow principles [26], which appear to have strong synergistic inter-relationships; systematically accounting for CBP parameters in the context of memory bound derivation (derivations of efficiently-computable upper bounds on memory requirements) [8]; and understanding the impact of CBP-based buffer optimization on retiming/vectorization transformations [35][36][37] for throughput optimization under memory capacity constraints. …”

Efficient Retiming of Multirate DSP Algorithms

“…The first set of SDFGs consists of four practical DSP applications, including a sample rate converter (Samplerate) [23], a satellite receiver (Satellite) [24], a maximum entropy spectrum analyzer (MaxES) [25], and a channel equalizer (CEer); the latter is converted from the cyclo-static dataflow model [26] in [27]. Adopting the method in [2], by introducing to each model a dummy actor with computation time zero and edges with proper rates and delays to connect the dummy actor to the actors that have no incoming edges or no outgoing edges, we convert these models to strongly connected graphs.…”