Energy efficient semi-partitioned scheduling for embedded multiprocessor streaming systems

• Published in: Design automation for embedded systems Vol. 20; no. 3; pp. 239 - 266
• Main Authors: Cannella, Emanuele, Stefanov, Todor P.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.09.2016
• Subjects: CAE) and Design; Circuits and Systems; Computer-Aided Engineering (CAD; Engineering; Special Purpose and Application-Based Systems; Embedded streaming systems; Model-based design; Energy-efficient design; Energy efficient multiprocessor scheduling; Real-time multiprocessor scheduling
• ISSN: 0929-5585; 1572-8080
• DOI: 10.1007/s10617-016-9176-2

In this paper, we study the problem of energy minimization when mapping streaming applications with throughput constraints to homogeneous multiprocessor systems in which voltage and frequency scaling is supported with a discrete set of operating voltage/frequency modes. We propose a soft real-time semi-partitioned scheduling algorithm which allows an even distribution of the utilization of tasks among the available processors. In turn, this enables processors to run at a lower frequency, which yields to lower energy consumption. We show on a set of real-life applications that our semi-partitioned scheduling approach achieves significant energy savings compared to a purely partitioned scheduling approach and an existing semi-partitioned one, EDF-os, on average by 36 % (and up to 64 %) when using the lowest frequency which guarantees schedulability and is supported by the system. By using a periodic frequency switching scheme that preserves schedulability, instead of this lowest supported fixed frequency, we obtain an additional energy saving up to 18 %. Although the throughput of applications is unchanged by the proposed semi-partitioned approach, the mentioned energy savings come at the cost of increased memory requirements and latency of applications.