Jung-Eun Kim
UIUC
jekim314@illinois.edu
Bio
Jung-Eun Kim is a PhD candidate advised by Prof. Lui Sha in the Department of Computer Science at the University of Illinois at Urbana-Champaign. She received her BS and MS (advised by Prof. Chang-Gun Lee) degrees from the department of Computer Science and Engineering of Seoul National University, Korea in 2007 and 2009, respectively. Her current research interests include real-time scheduling (schedulability analysis, optimization, hierarchical scheduling) and real-time multicore architecture. The main targeted application is safety-critical hard real-time systems such as avionics systems (Integrated modular avionics (IMA) systems). She is a recipient of the Richard T. Cheng Endowed Fellowship for 2015-2016.
A New Real-Time Scheduling Paradigm for Safety-Critical Multicore Systems
A New Real-Time Scheduling Paradigm for Safety-Critical Multicore Systems
Over the past decade, multicore processors have become increasingly common for their potential of efficiency, which has made new single-core processors become relatively scarce. As a result, it has created a pressing need to transition to multicore processors. However, existing safety-critical software that has been certified on single-core processors is not allowed to be fielded on a multicore system as is. The issue stems from, namely, serious inter-core interference problems on shared resources in current multicore processors, which create non-deterministic timing behavior. Meeting the timing constraints is the crucial requirement of safety-critical real-time systems as timing violations could have disastrous effects, from loss of human life to damages to machines and/or the environment. This is why Federal Aviation Administration (FAA) does not currently allow the use of more than one core in a multicore chip. Academia has paid little attention to non-determinism due to uncoordinated I/O communications relatively compared to other resources such as cache or memory, although industry considers it as one of the most troublesome challenges. Hence we focuse on I/O synchronization while assuming unknown Worst Case Execution Time (WCET) that can get impacted by other interference sources. Traditionally, a two-level scheduling, such as Integrated Modular Avionics system (IMA), has been used for providing temporal isolation capability. However, such hierarchical approaches introduce significant priority inversions across applications, especially in multicore systems, ultimately leading to lower system utilization. To address these issues, we have proposed a novel scheduling mechanism called budgeted generalized rate monotonic analysis (Budgeted GRMS) in which different applications’ tasks are globally scheduled for avoiding unnecessary priority inversions, yet the CPU resource is still partitioned for temporal isolation among applications. Incorporating the issues of unknown WCETs and I/O synchronization, this new scheduling paradigm enables the “safe” use of multicore processors in safety-critical real-time systems.