1996 Research Summaries for the Ptolemy Project
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Code Generation for Heterogeneous Multiprocessors
Researcher: | José Luis Pino
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Advisor: | Edward A. Lee
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Sponsors: | AT&T Bell Labs Fellowship, ARPA(RASSP) F33615-93-C-1317 and the Ptolemy Project |
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Today, programming of signal processing algorithms on embedded digital signal
processors is done in assembly language and scheduled by hand.
If the processor configuration changes, the code must be redesigned. If the
processors themselves change, the code must be completely rewritten. In
this project, we are interested in rapid prototyping of signal processing
applications. We have developed a code generation framework for
heterogeneous multiprocessor DSP systems from a high-level block diagram
specification [1]. Code generation
requires partitioning and scheduling of the algorithm onto the
multiprocessor architecture. Subsequently, the algorithm code is generated
in the appropriate languages.
The algorithm is specified using multiple independent dataflow graphs as described in
[2]. The independent
graphs communicate over nondeterminate communication links. These links do
not introduce data dependencies among the independent graphs. We have
found that this communication mechanism is ideal for specifying run-time
controls and displays for real-time signal processing applications.
An illustration of the use of such multiple dataflow graphs is shown in figure
1. Here we have the top-level
specification of an FM music synthesis algorithm. This application has
been targeted to a heterogeneous platform consisting of a Unix workstation
and a Motorola 56001 DSP board. In this example, there are five
independent dataflow graphs communicating over five nondeterminate links.
The C and Tcl/Tk code is generated for the Unix workstation; Motorola
56001 assembly code is generated for the DSP board.
The user interface, shown in figure 2,
is generated from the user specification.
- J. L. Pino, S. Ha, E. A. Lee, and J. T. Buck, ``Software
Synthesis for DSP Using Ptolemy,'' to appear in Journal of VLSI Signal
Processing, special issue on Synthesis for DSP, vol. 9, no.
1, 1995.
- J. L. Pino, T. M. Parks and E. A. Lee,
``Mapping
Multiple Independent Synchronous Dataflow Graphs onto Heterogeneous
Multiprocessors,'' Proceedings of the IEEE Asilomar Conference on
Signals, Systems, and Computers, Pacific Grove, CA, November 1994.
Send comments to
José Luis Pino
at pino@eecs.berkeley.edu.