A Delay Composition Theorem for Real-Time Pipelines

Uniprocessor schedulability theory made great strides, in part, due to the simplicity of composing the delay of a job from the execution times of higher-priority jobs that preempt it. In this paper, we bound the end-to-end delay of a job in a multistage pipeline as a function of higher-priority job execution times on different stages. We show that the end-toend delay is bounded by that of a single virtual “bottleneck” stage plus a small additive component. This contribution effectively transforms the pipeline into a single stage system. The wealth of schedulability analysis techniques derived for uniprocessors can then be applied to decide the schedulability of the pipeline. The transformation does not require imposing artitifical per-stage deadlines, but rather models the pipeline as a whole and uses the end-to-end deadlines directly in the single-stage analysis. It also does not make assumptions on job arrival patterns or periodicity and thus can be applied to periodic and aper...

• Type: Conference
• Year: 2007
• Where: ECRTS
• Authors: Praveen Jayachandran, Tarek F. Abdelzaher
• Keywords: ECRTS 2007, Schedulability Analysis, Schedulability Analysis Techniques, Uniprocessor Schedulability Theory