http://chess.eecs.berkeley.edu/

April 13, 2010 Center for Hybrid and Embedded Software Systems

Compositionality in Synchronous Data Flow

Stavros Tripakis

Dai Bui

Bert Rodiers

Edward A. Lee

Marc Geilen

• Model-based design for embedded software: build software starting from high-level models• Synchronous Data Flow (SDF): popular model in embedded systems, signal processing• Ptolemy II: heterogeneous modeling environment that includes hierarchical SDF models

Ongoing Work•Comparing clustering algorithms•Modular performance analysis•Refolding

Actor Firing Clustering

Unfolding SDF Schedule Graph

Greedy Backward Disjoint Clustering

Preliminary Implementation

Test Cases

Motivation: Incremental Compilation• Large Ptolemy models => long time to compile• Incremental compilation: generate code for parts of the model independently from others => modularity

References•S. Tripakis, D. Bui, B. Rodiers, and E.A. Lee. Compositionality in Synchronous Data Flow: Modular Code Generation from Hi- erarchical SDF Graphs.Technical Report UCB/EECS-2009-143, EECSDepartment, University of California, Berkeley, Oct 2009.•E.A. Lee and D.G. Messerschmitt. Static scheduling of synchronous data flow programs for digital signal processing. IEEE Trans. Comput., 36(1):24–35, 1987.•R. Lublinerman, C. Szegedy, and S. Tripakis. Modular code generation from synchronous block diagrams: modularity vs. code size. In Principles of Programming Languages – POPL’09, pages 78–89. ACM, January 2009.•J. Falk, J. Keinert, C. Haubelt, J. Teich, and S. Bhattacharyya. A generalized static data flow clustering algorithm for mpsoc scheduling of multimedia applications. In Embedded Software – EMSOFT’08, pages 189–198. ACM, 2008.

Hierarchical SDF Graphs

Problem: SDF is not Compositional• Abstracting composite SDF into atomic SDF can result to deadlocks during feedback

Our Proposal: Non-Monolithic Profiles• Each actor has multiple different firing functions

ContextProfile Synthesis

Rate Analysis

Deadlock Analysis