A Processor Extension for Time-Predictable Code Execution

In this paper, we present an instruction filter, a simple architecture extension that adds support for fully predicated execution to existing processor cores that do not natively support it. This makes single-path code execution and hence high quality and easily derivable worst-case execution time (WCET) information available for a wide range of processors. We have implemented the single-path instruction filter for two processors and evaluated it on the TACLe benchmark collection. The results demonstrate that despite the seeming inefficiency of single-path code, our method does not substantially increase the WCET. Therefore, running single-path code on processors with our instruction filter represents a competitive method for time-predictable code execution.