Institute of Embedded Systems

Note: hfalk, ESD

Abstract: This paper describes a set of novel high-level control flow transformations for performance improvement of typical address-dominated multimedia applications. We show that these transformations applied at the source code level can have a very large impact on execution time at the cost of limited overhead in code size for a broad range of instruction set processor families (i. e. CISC, RISC, DSP, VLIW, ...). For a profound evaluation, all transformations are applied to the C-codes of two real-life applications selected from the video and image processing domains. A detailed analysis of the effect of the transformations is done by compiling and executing the transformed programs on seven different programmable processors. The measured runtimes indicate quite significant improvements in all processor families when comparing the performance of the transformed codes to their initial version even when these are compiled using their native optimizing compilers with their most aggressive optimization features enabled. The average gains in execution time range from 40.2% and 87.7% depending on the driver, with an average overhead in code size between 21.1% and 100.9%.