Journal Article Presented at ECRTS 2019

Today, Ali presented our Real-time Systems article “Uneven Memory Regulation for Scheduling IMA Applications on Multi-core Platforms” in the Journal-to-conference (J2C) session at ECRTS.

This article addresses the problem of resource sharing in mixed-criticality systems through temporal isolation by extending the state-of-the-art Single-Core Equivalence (SCE) framework in three ways: 1) we extend the theoretical toolkit for the SCE framework by considering EDF and server-based scheduling, instead of partitioned fixed-priority scheduling, 2) we support uneven memory access budgets on a per-server basis, rather than just on a per-core basis, and 3) we formulate an Integer-Linear Programming Model (ILP) guaranteed to find a feasible mapping of a given set of servers to processors, including their execution time and memory access budgets, if such a mapping exists. Our experiments with synthetic task sets confirm that considerable improvement in schedulability can result from the use of per-server memory access budgets under the SCE framework.

Overall, I greatly appreciate that key conferences in the real-time community are starting to allow journal articles to be presented. This increases the exposure of these works that are often longer and better edited. It is also helpful for researchers at the institutes where conference publications are not considered a relevant KPI. You can argue the validity of this reasoning in areas of computer science where conferences are highly competitive with 20-30% acceptance rates, but it is reality for some researchers. An interesting thing with the MODELS conference is that they collaborate with the SOSYM journal such that some accepted articles in the journal gets a full slot at the conference. This is a nice way to highlight good articles and to appreciate the work done by both authors and reviewers.

Paper Accepted at EMSOFT 2019

Our collaboration with CISTER has been extremely fruitful this year, as yet another paper in our research line on mixed-criticality scheduling has been accepted. This latest paper is entitled “Techniques and Analysis for Mixed-criticality Scheduling with Mode-dependent Server Execution Budgets” and has been accepted at the International Conference on Embedded Software (EMSOFT).

The goal of this work is, like many other in this research line, is to reduce cost of mixed-criticality systems. This time, we achieve this by addressing the limitation that a server only has a single execution budget in all modes, despite that their computational requirements may vary significantly. More specifically, the three main contributions of the paper are: 1) a scheduling arrangement for uni-processor systems employing fixed-priority scheduling within periodic servers, whose budgets are dynamically adjusted at run-time in the event of a mode change, 2) a new schedulability analysis for such systems, and 3) heuristic algorithms for assigning budgets to servers in different modes and ordering the execution of the servers. Experiments with synthetic task sets demonstrate considerable improvements (up to 52.8%)