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Advisor(s)
Abstract(s)
The design of mixed-criticality systems often involves painful tradeoffs between safety guarantees
and performance. However, the use of more detailed architectural models in the design and
analysis of scheduling arrangements for mixed-criticality systems can provide greater confidence
in the analysis, but also opportunities for better performance. Motivated by this view, we propose
an extension of Vestal’s model for mixed-criticality multicore systems that (i) accounts for the
per-task partitioning of the last-level cache and (ii) supports the dynamic reassignment, for
better schedulability, of cache portions initially reserved for lower-criticality tasks to the highercriticality
tasks, when the system switches to high-criticality mode. To this model, we apply
partitioned EDF scheduling with Ekberg and Yi’s deadline-scaling technique. Our schedulability
analysis and scalefactor calculation is cognisant of the cache resources assigned to each task, by
using WCET estimates that take into account these resources. It is hence able to leverage the
dynamic reconfiguration of the cache partitioning, at mode change, for better performance, in
terms of provable schedulability. We also propose heuristics for partitioning the cache in lowand
high-criticality mode, that promote schedulability. Our experiments with synthetic task sets,
indicate tangible improvements in schedulability compared to a baseline cache-aware arrangement
where there is no redistribution of cache resources from low- to high-criticality tasks in the event
of a mode change.
Description
29th Euromicro Conference on Real-Time Systems (ECRTS 2017). 27 to 30, Jun, 2017, Main track, pp 18:1-18:21. Dubrovnik, Croatia.
Keywords
Mixed criticality scheduling Vestal model Dynamic redistribution of shared cache Shared last-level cache analysis Cache-aware scheduling
Citation
Publisher
Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik