End-to-End Schedulability Analysis for Bi-directional Real-Time Multistage Pipeline

In this paper we discuss the end-to-end schedulability analysis for the bi-directional multistage pipeline systems, in which the arriving tasks could traverse the pipeline nodes in either of the two opposite directions. By accounting for the task execution overlap among nodes, we could derive an end-to-end delay bound formula for each task, which transforms the schedulability analysis of the task in the pipeline system into the schedulability analysis of that task in a corresponding single node system essentially, then the uniprocessor schedulability analysis theory could be applied to test the schedulability of this task in the original pipeline system. This transformation makes no assumptions on task arrival patterns and thus could be applied to both periodic and a periodic arrival patterns. We compare this technique with previous pipeline schedulability test techniques and show by simulations that our technique could derive better end-to-end delay bound except when node count is small and the ratio of deadline to period is large.