Institute for Communication Technologies and Embedded Systems

DSPstone

DSP Compiler and Processor Evaluation - DSPstone

How good are Compilers for DSP-architectures ?

This was the question in 1995 when we started to measure the performance of commercial available DSP-compilers. The performance was measured in such a way that the code produced by the compiler was compared to hand-written assembly code.

The difference between theses two implementations is measured in terms of code-size and execution time. This was done for several architectures in order to gain information about the abilities of the compilers to address certain features of the architecture.

Having a look at the Analog Devices DSP we clearly see that the handwritten assembly code almost outperforms the code produced by the compiler. The execution of the compiler generated code takes 8 times longer than the one written by hand. The code size also is significantly larger. This means if you develop your application with such a compiler you'll have to take a much faster DSP, spend more money for external memory. As a result nearly all time-critical applications are implemented by hand. Some of the reasons why DSP-Compilers are so bad are:

  • unability to use machine idioms (MAC-operation)
  • unability to make use of certain architectural features (zero overhead loops)
  • unability to make use of possible instruction level parallelism

Most of the DSP-compilers are based on GPP-(general purpose-processor) compilers. Therefore the results are not very surprising.

Download the official DSP-Stone sources and theDSP-Stone report here. Updated sources for the TI TMS320C54x are available, too.

Projects of the Group on DSP Tools

Publications

Willems, M., Zivojnovic, V. and Meyr, H.: DSP-Compiler: Produktqualität für kontrolldominierte Applikationen?, in Proceedings of DSP Deutschland 96, pp. 49-56, Oct. 1996
Willems, M. and Zivojnovic, V.: DSP-Compiler: Product Quality for Control-Dominated Applications?, in Proc. Int. Conf. on Signal Processing Application and Technology (ICSPAT)(Boston), pp. 752-756, Oct. 1996
Willems, M., Warmers, M. and Zivojnovic, V.: DSP-Compiler: auf dem Weg zum Produktionstool ?, in Design & Elektronik, pp. 47-48, Dec. 1995
Zivojnovic, V., Schraut, H., Willems, M. and Schoenen, R.: DSPs, GPPs, and multimedia applications: An evaluation using DSPstone, in Proc. Int. Conf. on Signal Processing Application and Technology (ICSPAT)(Boston), Oct. 1995
Willems, M., Jersak, M. and Zivojnovic, V.: DSP-bezogene Spracherweiterungen: Möglichkeiten und Grenzen, in Proc. of DSP Deutschland 95, München, pp. 100-110, Oct. 1995
Zivojnovic, V., Martinez, J., Schläger, C. and Meyr, H.: DSPstone: A DSP-Oriented Benchmarking Methodology, in Proc. of ICSPAT'94 - Dallas, Oct. 1994