Title
Techniques and analysis for mixed-criticality scheduling with mode-dependent server execution budgets
Author
Awan, M.A.
Bletsas, K.
Souto, P.F.
Akesson, B.
Tovar, E.
Publication year
2019
Abstract
In mixed-criticality systems, tasks of different criticality share system resources, mainly to reduce cost. Cost is further reduced by using adaptive mode-based scheduling arrangements, such as Vestal's model, to improve resource efficiency, while guaranteeing schedulability of critical functionality. To simplify safety certification, servers are often used to provide temporal isolation between tasks. In its simplest form, a server is a periodically recurring time window, in which some tasks are scheduled. A server's computational requirements may greatly vary in different modes, although state-of-the-art techniques and schedulability tests do not allow different budgets to be used by a server in different modes. This results in a single conservative execution budget for all modes, increasing system cost. The goal of this paper is to reduce the cost of mixed-criticality systems through three main contributions: (i) a scheduling arrangement for uniprocessor systems employing fixed-priority scheduling within periodic servers, whose budgets are dynamically adjusted at run-time in the event of a mode change, (ii) a new schedulability analysis for such systems, and (iii) 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%) in scheduling success ratio when using dynamic server budgets vs. static “one-size-fits-all-modes” budgets.
Subject
Computer systems organization
Real-timesystems
Real-time operating systems
Real-time system architecture
Real-time systems
Mixed-criticality scheduling
Vestalmodel
Modechange
Server-based scheduling
Synamic execution
Budget
Timing isolation
To reference this document use:
http://resolver.tudelft.nl/uuid:cb1dcede-7801-41f5-8369-53b91318265c
DOI
https://doi.org/10.1145/3358234
TNO identifier
869617
Publisher
Association for Computing Machinery
ISSN
1539-9087
Source
ACM Transactions on Embedded Computing Systems
Article number
a109
Document type
conference paper