On static WCET analysis vs. run-time monitoring of execution time

2004 ◽  
Author(s):  
C.D. Cavanaugh
Keyword(s):  
Execution Time ◽  
Wcet Analysis ◽  
Run Time

scholarly journals Estimation Accuracy on Execution Time of Run-Time Tasks in a Heterogeneous Distributed Environment

Sensors ◽  
2016 ◽  
Vol 16 (9) ◽  
pp. 1386 ◽  
Author(s):  
Qi Liu ◽  
Weidong Cai ◽  
Dandan Jin ◽  
Jian Shen ◽  
Zhangjie Fu ◽  
...  
Keyword(s):  
Execution Time ◽  
Estimation Accuracy ◽  
Distributed Environment ◽  
Run Time

Interactive WCET Prediction with Warning for Timeout Risk

2017 ◽  
Vol 31 (05) ◽  
pp. 1750012 ◽  
Author(s):  
Fanqi Meng ◽  
Xiaohong Su ◽  
Zhaoyang Qu
Keyword(s):  
Execution Time ◽  
Control Flow ◽  
Real Time Systems ◽  
Wcet Analysis ◽  
Running Speed ◽  
Worst Case ◽  
Worst Case Execution Time ◽  
Level Model ◽  
Hard Real Time ◽  
Time Systems

Worst case execution time (WCET) analysis is essential for exposing timeliness defects when developing hard real-time systems. However, it is too late to fix timeliness defects cheaply since developers generally perform WCET analysis in a final verification phase. To help developers quickly identify real timeliness defects in an early programming phase, a novel interactive WCET prediction with warning for timeout risk is proposed. The novelty is that the approach not only fast estimates WCET based on a control flow tree (CFT), but also assesses the estimated WCET with a trusted level by a lightweight false path analysis. According to the trusted levels, corresponding warnings will be triggered once the estimated WCET exceeds a preset safe threshold. Hence developers can identify real timeliness defects more timely and efficiently. To this end, we first analyze the reasons of the overestimation of CFT-based WCET calculation; then we propose a trusted level model of timeout risks; for recognizing the structural patterns of timeout risks, we develop a risk data counting algorithm; and we also give some tactics for applying our approach more effectively. Experimental results show that our approach has almost the same running speed compared with the fast and interactive WCET analysis, but it saves more time in identifying real timeliness defects.

scholarly journals A Design-Time/Run-Time Application Mapping Methodology for Predictable Execution Time in MPSoCs

2018 ◽  
Vol 17 (5) ◽  
pp. 1-25 ◽  
Author(s):  
Andreas Weichslgartner ◽  
Stefan Wildermann ◽  
Deepak Gangadharan ◽  
Michael Glaß ◽  
Jürgen Teich
Keyword(s):  
Execution Time ◽  
Application Mapping ◽  
Design Time ◽  
Run Time

Colored Petri Nets Based Fault Diagnosis in Service Oriented Architecture

2018 ◽  
Vol 15 (4) ◽  
pp. 1-28 ◽  
Author(s):  
Guru Prasad Bhandari ◽  
Ratneshwer Gupta ◽  
Satyanshu K. Upadhyay
Keyword(s):  
Fault Diagnosis ◽  
Petri Nets ◽  
Execution Time ◽  
Service Oriented Architecture ◽  
Service Providers ◽  
Black Box ◽  
Colored Petri Nets ◽  
Service Oriented ◽  
Run Time ◽  
Software Services

Diagnosing faults in a service-oriented architecture (SOA) is a difficult task due to limited accessibility of software services. Probabilistic approaches of diagnostic faults may be insufficient due to the black-box nature of services. In SOA, software services may be obtained by different service providers and get composed at run-time. This is the reason why there are diagnosis faults at execution time, and is a costly affair. The authors have demonstrated a Color Petri Nets (CPN)-based approach to model different faults that may occur at execution time. Some heuristics are proposed to diagnose faults from the CPN modeling. CPN behavioral properties have also been used for fault diagnosis. The model may be helpful for dependability enhancement of an SOA-based systems.

scholarly journals Self-Adaptive Run-Time Variable Floating-Point Precision for Iterative Algorithms: A Joint HW/SW Approach

Electronics ◽  
2021 ◽  
Vol 10 (18) ◽  
pp. 2209
Author(s):  
Noureddine Ait Said ◽  
Mounir Benabdenbi ◽  
Katell Morin-Allory
Keyword(s):  
Power Consumption ◽  
Execution Time ◽  
Energy Savings ◽  
Iterative Algorithms ◽  
Time Variable ◽  
Floating Point ◽  
Double Precision ◽  
Time Saving ◽  
Variable Precision ◽  
Run Time

Using standard Floating-Point (FP) formats for computation leads to significant hardware overhead since these formats are over-designed for error-resilient workloads such as iterative algorithms. Hence, hardware FP Unit (FPU) architectures need run-time variable precision capabilities. In this work, we propose a new method and an FPU architecture that enable designers to dynamically tune FP computations’ precision automatically at run-time called Variable Precision in Time (VPT), leading to significant power consumption, execution time, and energy savings. In spite of its circuit area overhead, the proposed approach simplifies the integration of variable precision in existing software workloads at any level of the software stack (OS, RTOS, or application-level): it only requires lightweight software support and solely relies on traditional assembly instructions, without the need for a specialized compiler or custom instructions. We apply the technique on the Jacobi and the Gauss–Seidel iterative methods taking full advantage of the suggested FPU. For each algorithm, two modified versions are proposed: a conservative version and a relaxed one. Both algorithms are analyzed and compared statistically to understand the effects of VPT on iterative applications. The implementations demonstrate up to 70.67% power consumption saving, up to 59.80% execution time saving, and up to 88.20% total energy saving w.r.t the reference double precision implementation, and with no accuracy loss.

scholarly journals Flexible Mixed-Criticality Scheduling with Dynamic Slack Management

2021 ◽  
Vol 30 (10) ◽  
pp. 2150306
Author(s):  
Xinyang Dong ◽  
Gang Chen ◽  
Mingsong Lv ◽  
Weiguang Pang ◽  
Wang Yi
Keyword(s):  
Quality Of Service ◽  
Execution Time ◽  
Time Behavior ◽  
Task Execution ◽  
Early Completion ◽  
Research Attention ◽  
The Past ◽  
Run Time ◽  
Mixed Criticality

Mixed-criticality (MC) system has attracted a lot of research attention in the past few years for its resource efficiency. Recent work attempted to provide a new MC model, the so-called Flexible Mixed-Criticality (FMC) task model, to relax the pessimistic assumptions in classic MC scheduling. However, in FMC, the behavior of MC tasks is still analyzed in offline stage. The run-time behavior such as dynamic slack has not yet been studied in FMC scheduling framework. In this paper, we present a utilization-based slack scheduling framework for FMC tasks. In particular, we monitor task execution on run time and collect dynamic slacks generated by task early completion. And these slacks can then be used either by high-criticality tasks to reduce mode-switches, or by low-criticality tasks so that less suspensions are triggered with more execution time, and thus quality of service is improved. We evaluate our approach with extensive simulations, and experiment results demonstrate the effectiveness of the proposed approaches.

scholarly journals On the expressiveness of π-calculus for encoding mobile ambients

2016 ◽  
Vol 28 (2) ◽  
pp. 202-240 ◽  
Author(s):  
LINDA BRODO
Keyword(s):  
Execution Time ◽  
Transition System ◽  
Flat Channel ◽  
Π Calculus ◽  
Run Time ◽  
Support Methods ◽  
Ambient Calculus ◽  
Mobile Ambients

We investigate the expressiveness of two classical distributed paradigms by defining the first encoding of the pure mobile ambient calculus into the synchronous π-calculus. Our encoding, whose correctness has been proved by relying on the notion of operational correspondence, shows how the hierarchical ambient structure can be reformulated within a flat channel interconnection amongst independent processes, without centralised control. To easily handle the computation for simulating a capability, we introduce the notions of simulating trace (representing the computation that a π-calculus process has to execute to mimic a capability) and of aborting trace (representing the computation that a π-calculus process executes when the simulation of a capability cannot succeed). Thus, the encoding may introduce loops, but, as it will be shown, the number of steps of any trace, therefore of any aborting trace, is limited, and the number of states of the transition system of the encoding processes still remains finite. In particular, an aborting trace makes a sort of backtracking, leaving the involved sub-processes in the same starting configurations. We also discuss two run-time support methods to make these loops harmless at execution time. Our work defines a relatively simple, direct, and precise translation that reproduces the ambient structure by means of channel links, and keeps track of the dissolving of an ambient.

A Worst-Case Execution Time Analysis Approach Based on AOE Networks

2013 ◽  
Vol 791-793 ◽  
pp. 1726-1729
Author(s):  
Liang Liang Kong ◽  
Lin Chen
Keyword(s):  
Directed Graph ◽  
Execution Time ◽  
Experimental Results ◽  
Analysis Approach ◽  
Time Analysis ◽  
Wcet Analysis ◽  
Worst Case ◽  
Weighted Directed Graph ◽  
Worst Case Execution Time ◽  
Longest Path

To overcome disadvantages of traditional worst-case execution time (WCET) analysis approaches, this paper proposes a new WCET analysis approach based on AOE networks for ARM programs. By assigning the execution times of program segments to weights of directed edges, we reformulated the analysis of the WCET of the program as finding the longest path in a weighted directed graph. An algorithm implemented in this paper is used to search the longest path in the weighted directed graph and gives the WCET estimate finally. Experimental results have shown the analysis approach proposed in this paper is an effective way to obtain the safe and tight WCET estimate for ARM programs.

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