Integrating Cache Related Pre-emption Delay Analysis into EDF Scheduling

Cache memories have been introduced into embedded systems to prevent memory access times from becoming an unacceptable performance bottleneck. Memory and cache are split into blocks containing instructions and data. During a pre-emption, blocks from the pre-empting task can evict those of the pre-empted task. When the pre-empted task is resumed, if it then has to re-load the evicited blocks, cache related pre-emption delays (CRPD) are introduced which then affect schedulability of the task. In this paper, we show how existing approaches for calculating CRPD for FP scheduling can be adapted and integrated into schedulability analysis for EDF. We then compare the performance of the different approaches against an existing approach for calculating CRPD for EDF. Using a case study and empirical evaluation, we show the benefits of our CRPD analysis.