Next Article in Journal
A Modified Version of the RNG kε Turbulence Model for the Scale-Resolving Simulation of Internal Combustion Engines
Next Article in Special Issue
Multi-Phase Modular Drive System: A Case Study in Electrical Aircraft Applications
Previous Article in Journal
Chance-Constrained Real-Time Dispatch with Renewable Uncertainty Based on Dynamic Load Flow
Previous Article in Special Issue
A Novel Digital Control Method of a Single-Phase Grid-Connected Inverter Based on a Virtual Closed-Loop Circuit and Complex Vector Representation
Article Menu
Issue 12 (December) cover image

Export Article

Open AccessArticle
Energies 2017, 10(12), 2113; https://doi.org/10.3390/en10122113

Reducing WCET Overestimations by Correcting Errors in Loop Bound Constraints

1,2
and
1,*
1
School of Computer Science and Technology, Harbin Institute of Technology, Harbin 150001, China
2
School of Information Engineering, Northeast Electric Power University, Jilin 132012, China
*
Author to whom correspondence should be addressed.
Received: 12 November 2017 / Revised: 3 December 2017 / Accepted: 12 December 2017 / Published: 12 December 2017
Full-Text   |   PDF [4663 KB, uploaded 14 December 2017]   |  

Abstract

In order to reduce overestimations of worst-case execution time (WCET), in this article, we firstly report a kind of specific WCET overestimation caused by non-orthogonal nested loops. Then, we propose a novel correction approach which has three basic steps. The first step is to locate the worst-case execution path (WCEP) in the control flow graph and then map it onto source code. The second step is to identify non-orthogonal nested loops from the WCEP by means of an abstract syntax tree. The last step is to recursively calculate the WCET errors caused by the loose loop bound constraints, and then subtract the total errors from the overestimations. The novelty lies in the fact that the WCET correction is only conducted on the non-branching part of WCEP, thus avoiding potential safety risks caused by possible WCEP switches. Experimental results show that our approach reduces the specific WCET overestimation by an average of more than 82%, and 100% of corrected WCET is no less than the actual WCET. Thus, our approach is not only effective but also safe. It will help developers to design energy-efficient and safe real-time systems. View Full-Text
Keywords: real-time system; software safety; WCET analysis; worst-case execution path; loop bound real-time system; software safety; WCET analysis; worst-case execution path; loop bound
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Meng, F.; Su, X. Reducing WCET Overestimations by Correcting Errors in Loop Bound Constraints. Energies 2017, 10, 2113.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Energies EISSN 1996-1073 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top