Abstract
As from Ada 2005, the language has supported different dispatching policies including fixed priority (FP) and earliestdeadline first (EDF). EDF dispatching can be applied across the whole range of priorities or across a restricted range. In this way, EDF scheduling is integrated into a FP framework. Baker's Stack Resource Policy (SRP) is also integrated with Ada's immediate priority ceiling protocol to support resource sharing using protected objects. However, with the introduction of support for global, partitioned and cluster scheduling for multiprocessor systems, the use of protected objects in applications needs to be re-evaluated. This is because Ada does not completely define how protected objects are accessed in a multiprocessor environment and because the SRP cannot be directly applied to multiprocessors.
This paper reviews the currently available multiprocessor resource allocation policies and analyzes their applicability to Ada. It proposes some new Ada mechanisms that would facilitate the programming of a variety of protected object access protocols.
- T. P. Baker. Stack-based scheduling for realtime processes. Real-Time Syst., 3:67--99, March 1991 Google Scholar
Digital Library
- A. Block, H. Leontyev, B. B. Brandenburg, and J. H. Anderson. A flexible real-time locking protocol for multiprocessors. In Proceedings of the 13th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications, RTCSA '07, pages 47--56, Washington, DC, USA, 2007. IEEE Computer Society. Google Scholar
Digital Library
- B. B. Brandenburg, J. M. Calandrino, A. Block, H. Leontyev, and J. H. Anderson. Real-time synchronization on multiprocessors: To block or not to block, to suspend or spin? In Proceedings of the 2008 IEEE Real-Time and Embedded Technology and Applications Symposium, pages 342--353, Washington, DC, USA, 2008. IEEE Computer Society. Google Scholar
Digital Library
- B.B. Brandenburg and J.H. Anderson. Optimality results for multiprocessor real-time locking. In Real-Time Systems Symposium (RTSS), 2010 IEEE 31st, pages 49--60, 30 2010-dec. 3 2010. Google Scholar
Digital Library
- B.B. Brandenburg and J.H. Anderson. Real-time resource sharing under cluster scheduling. In EMSOFT, page submitted, 2011. Google Scholar
Digital Library
- Y. Chang, R. I. Davis, and A. J.Wellings. Reducing queue lock pessimism in multiprocessor schedulability analysis. In Proceedings of 18th International Conference on Real-Time and Network Systems (RTNS), pages 99--108, 2010.Google Scholar
- Y. Chang, R.I. Davis, and A.J. Wellings. Improved schedulability analysis for multiprocessor systems with resource sharing. techreport YCS-2010-454, University of York, 2010.Google Scholar
- A. Easwaran and B. Andersson. Resource sharing in global fixed-priority preemptive multiprocessor scheduling. In IEEE Real-Time Systems Symposium, pages 377--386, 2009. Google Scholar
Digital Library
- P. Gai, G. Lipari, and M. Di Natale. Minimizing memory utilization of real-time task sets in single and multi-processor systems-on-a-chip. In Real-Time Systems Symposium, 2001. (RTSS 2001). Proceedings. 22nd IEEE, pages 73--83, 2001. Google Scholar
Digital Library
- P. Gai, M. Di Natale, G. Lipari, A. Ferrari, C. Gabellini, and P. Marceca. A comparison of MPCP and MSRP when sharing resources in the janus multiple-processor on a chip platform. In Proceedings of the The 9th IEEE Real-Time and Embedded Technology and Applications Symposium, RTAS '03, pages 189--, Washington, DC, USA, 2003. IEEE Computer Society. Google Scholar
Digital Library
- M. G. Harbour M. A. Rivas. Application-defined scheduling in Ada. In Proceedings of IRTAW 12, Ada Letters, Vol XXIII(4), pages 42--51, 2003. Google Scholar
Digital Library
- R. Rajkumar. Synchronization in Real-Time Systems: A Priority Inheritance Approach. Kluwer Academic Publishers, 1991. Google Scholar
Digital Library
- R. Rajkumar, L. Sha, and J.P. Lehoczky. Real-time synchronization protocols for multiprocessors. In Real-Time Systems Symposium, 1988., Proceedings., pages 259--269, 1988.Google Scholar
Cross Ref
- R. Rajkumar, L. Sha, and J.P. Lehoczky. Real-time synchronization protocols for shared memory multiprocessors. In Proceedings of the 10th International Conference on Distributed Computing, pages 116--125, 1990.Google Scholar
Cross Ref
- J. Ras and A. M. K. Cheng. An evaluation of the dynamic and static multiprocessor priority ceiling protocol and the multiprocessor stack resource policy in an SMP system. In Proceedings of the 2009 15th IEEE Symposium on Real-Time and Embedded Technology and Applications, RTAS '09, pages 13--22, Washington, DC, USA, 2009. IEEE Computer Society. Google Scholar
Digital Library
- P. Rogers and A.J. Wellings. Openada: Compile-time reflection for Ada 95. In Albert Llamos and Alfred Strohmeier, editors, Reliable Software Technologies - Ada-Europe 2004, volume 3063 of Lecture Notes in Computer Science, pages 166--177. Springer Berlin / Heidelberg, 2004.Google Scholar
- A. Zerzelidis, A. Burns, and A. J. Wellings. Correcting the EDF protocol in Ada 2005. Ada Letters, XXVII:18--22, April 2007. Google Scholar
Digital Library
Index Terms
Ada 2012: resource sharing and multiprocessors
Recommendations
A real-time framework for multiprocessor platforms using Ada 2012
Ada-Europe'11: Proceedings of the 16th Ada-Europe international conference on Reliable software technologiesThe next release of the Ada language, Ada 2012, will probably incorporate explicit support for multiprocessor execution platforms. However, the implementation of multiprocessor scheduling approaches over the low-level abstractions offered by Ada forces ...
Application-defined scheduling in Ada
IRTAW '03: Proceedings of the 12th international workshop on Real-time AdaThis paper is a proposal for an application program interface (API) that would enable Ada applications to use application-defined scheduling algorithms in a way compatible with the scheduling model of the Ada 95 Real-Time Systems Annex. With this API, ...
Going real-time with Ada 2012 and GNAT
This paper provides an overview of the real-time additions to Ada 2012 and their implementation status in GNAT. Most of these additions are related to multiprocessors, helping to exploit parallelism in an efficient and predictable way, and this is the ...






Comments