ABSTRACT
Fixed-priority multicore schedulers are often preferable to dynamic-priority ones because they entail less overhead, are easier to implement, and enable certain tasks to be favored over others. Under global fixed-priority (G-FP) scheduling, as applied to the standard sporadic task model, response times for low-priority tasks may be unbounded, even if total task-system utilization is low. In this paper, it is shown that this negative result can be circumvented if different jobs of the same task are allowed to execute in parallel. In particular, a response-time bound is presented for task systems that allow intra-task parallelism. This bound merely requires that total utilization does not exceed the overall processing capacity---individual task utilizations need not be further restricted. This result implies that G-FP is optimal for scheduling soft real-time tasks that require bounded tardiness, if intra-task parallelism is allowed.
- T. Baker. Comparison of empirical success rates of global vs. partitioned fixed-priority and EDF scheduling for hard real time. Technical Report TR-050601, Department of Computer Science, Florida State University, 2005.Google Scholar
- T. Baker and S. Baruah. An analysis of global EDF schedulability for arbitrary-deadline sporadic task systems. Real-Time Systems, 43(1):3--24, 2009. Google ScholarDigital Library
- S. Baruah and T. Baker. Schedulability analysis of global EDF. Real-Time Systems, 38(3):223--235, 2008. Google ScholarDigital Library
- S. Baruah and N. Fisher. Global fixed-priority scheduling of arbitrary-deadline sporadic task systems. In Proceedings of the 9th International Conference on Distributed Computing and Networking, pages 215--226, 2008. Google ScholarDigital Library
- M. Bertogna, M. Cirinei, and G. Lipari. Improved schedulability analysis of EDF on multiprocessor platforms. In Proceedings of the 17th Euromicro Conference on Real-Time Systems, pages 209--218, 2005. Google ScholarDigital Library
- R. Davis and A. Burns. Priority assignment for global fixed-priority preemptive scheduling in multiprocessor real-time systems. In Proceedings of the 30th IEEE Real-Time Systems Symposium, pages 398--409, 2009. Google ScholarDigital Library
- U. Devi. Soft Real-Time Scheduling on Multiprocessors. PhD thesis, University of North Carolina at Chapel Hill, 2006. Google ScholarDigital Library
- U. Devi and J. Anderson. Tardiness bounds for global EDF scheduling on a multiprocessor. In Proceedings of the 26th IEEE Real-Time Systems Symposium, pages 330--341, 2005. Google ScholarDigital Library
- U. Devi and J. Anderson. Tardiness bounds under global EDF scheduling on a multiprocessor. Real-Time Systems, 38(2):133--189, 2008. Google ScholarDigital Library
- J. Erickson and J. Anderson. Response time bounds for GEDF without intra-task precedence constraints. In Proceedings of the 15th International Conference On Principles Of Distributed Systems, pages 128--142, 2011. Google ScholarDigital Library
- H. Leontyev and J. Anderson. Tardiness bounds for EDF scheduling on multispeed multicore platforms. In Proceedings of the 13th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications, pages 103--110, 2007. Google ScholarDigital Library
- K. Yang and J. Anderson. Optimal GEDF-based schedulers that allow intra-task parallelism on heterogeneous multiprocessors. In Proceedings of the 12th IEEE Symposium on Embedded Systems for Real-Time Multimedia, pages 30--39, 2014.Google ScholarCross Ref
- K. Yang, M. Yang, and J. Anderson. Reducing response-time bounds for DAG-based task systems on heterogeneous multicore platforms. In Proceedings of the 24th International Conference on Real-Time Networks and Systems, pages 349--358, 2016. Google ScholarDigital Library
- M. Yang, T. Amert, K. Yang, N. Otterness, J. Anderson, F. D. Smith, and S. Wang. Making OpenVX really 'real time'. In Proceedings of the 39th IEEE Real-Time Systems Symposium, to appear, 2018.Google Scholar
Index Terms
- Tardiness Bounds for Fixed-Priority Global Scheduling without Intra-Task Precedence Constraints
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