Messages in this thread | | | Date | Wed, 15 Jul 2009 00:25:26 -0400 | From | "Bjoern B. Brandenburg" <> | Subject | Re: RFC for a new Scheduling policy/class in the Linux-kernel |
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Quoting "James H. Anderson" <anderson@cs.unc.edu>: > Ted Baker did some work on an algorithm called EDZL > (EDF until zero laxity) that is essentially a hybrid of these two > algorithms. In simulations we've done (not based on real implementations), > EDZL exhibits really low tardiness (almost non-existent). EDZL may > give you the benefits of using laxities where useful and be easier > to implement (but that's just my guess)
EDZL has nice properties but may be hard to implement efficiently because it requires (a lot of) fine-grained timers. However, Shinpei Kato and Nobuyuki Yamasaki (CC'ed) presented an EDZL-derived scheduler called EDCL at RTCSA'08 that has similar performance guarantees but only does priority promotions at the release and completion times of jobs (hence, no additional timers are required).
Global EDF-based Scheduling with Efficient Priority Promotion Shinpei Kato and Nobuyuki Yamasaki Proceedings of the 14th International Conference on Embedded and Real-Time Computing Systems and Applications, pages 197-206. IEEE, 2008. http://www.ny.ics.keio.ac.jp/members/shinpei/papers/rtcsa08.pdf
I know that Shinpei and friends implemented EDCL on top of LITMUS^RT, but I never got around to incorporating the patches into the "official" LITMUS^RT patch. (Sorry, Shinpei!)
Regarding the comments about the availability of academic papers (which were also voiced repeatedly at OSPERT'09), I'd like to point out that you can find almost any recent paper by searching for the title with scholar.google.com and clicking on the "All XYZ versions" link... most researches make PDFs available on their homepages.
- Björn
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