scholarly journals Measurement-Based Worst-Case Execution Time Estimation Using the Coefficient of Variation

2017 ◽  
Vol 22 (4) ◽  
pp. 1-29 ◽  
Author(s):  
Jaume Abella ◽  
Maria Padilla ◽  
Joan Del Castillo ◽  
Francisco J. Cazorla
Keyword(s):  
Coefficient Of Variation ◽  
Execution Time ◽  
Time Estimation ◽  
Worst Case ◽  
Worst Case Execution Time

Use of Measurements in Worst-Case Execution Time Estimation for Real-Time Systems

2021 ◽  
Author(s):  
Jessica Junia Santillo Costa ◽  
Romulo Silva de Oliveira ◽  
Luis Fernando Arcaro
Keyword(s):  
Real Time ◽  
Execution Time ◽  
Time Estimation ◽  
Real Time Systems ◽  
Worst Case ◽  
Worst Case Execution Time ◽  
Time Systems

An Overview of Worst-Case Execution Time Estimation for Embedded Programs

2014 ◽  
Vol 651-653 ◽  
pp. 624-629
Author(s):  
Liang Liang Kong ◽  
Lin Xiang Shi ◽  
Lin Chen
Keyword(s):  
Embedded Systems ◽  
Real Time ◽  
Execution Time ◽  
Time Estimation ◽  
Worst Case ◽  
Performance Metric ◽  
Worst Case Execution Time ◽  
Hard Real Time ◽  
Time Systems

Most embedded systems are real-time systems, so real-time is an important performance metric for embedded systems. The worst-case execution time (WCET) estimation for embedded programs could satisfy the requirement of hard real-time evaluation, so it is widely used in embedded systems evaluation. Based on sufficient survey on the progress of WCET estimation around the world, it proposes a new classification of WCET estimation. After introducing the principle of WCET estimation, it mainly demonstrates various types of technologies to estimate WCET and classifies them into two main streams, namely, static and dynamic WCET estimations. Finally, it shows the development of WCET analysis tools.

scholarly journals A RISC-V Processor Design for Transparent Tracing

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1873
Author(s):  
Iván Gamino del Río ◽  
Agustín Martínez Hellín ◽  
Óscar R. Polo ◽  
Miguel Jiménez Arribas ◽  
Pablo Parra ◽  
...  
Keyword(s):  
Execution Time ◽  
Time Estimation ◽  
Use Case ◽  
Hybrid Analysis ◽  
Worst Case ◽  
Code Analysis ◽  
Static Code Analysis ◽  
Worst Case Execution Time ◽  
Code Instrumentation ◽  
Time Overhead

Code instrumentation enables the observability of an embedded software system during its execution. A usage example of code instrumentation is the estimation of “worst-case execution time” using hybrid analysis. This analysis combines static code analysis with measurements of the execution time on the deployment platform. Static analysis of source code determines where to insert the tracing instructions, so that later, the execution time can be captured using a logic analyser. The main drawback of this technique is the overhead introduced by the execution of trace instructions. This paper proposes a modification of the architecture of a RISC pipelined processor that eliminates the execution time overhead introduced by the code instrumentation. In this way, it allows the tracing to be non-intrusive, since the sequence and execution times of the program under analysis are not modified by the introduction of traces. As a use case of the proposed solution, a processor, based on RISC-V architecture, was implemented using VHDL language. The processor, synthesized on a FPGA, was used to execute and evaluate a set of examples of instrumented code generated by a “worst-case execution time” estimation tool. The results validate that the proposed architecture executes the instrumented code without overhead.

scholarly journals Reducing WCET Overestimations in Multi-Thread Loops with Critical Section Usage

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1747
Author(s):  
Simona Ramanauskaite ◽  
Asta Slotkiene ◽  
Kornelija Tunaityte ◽  
Ivan Suzdalev ◽  
Andrius Stankevicius ◽  
...  
Keyword(s):  
Execution Time ◽  
Timing Analysis ◽  
Time Estimation ◽  
Calculation Model ◽  
Critical Section ◽  
Worst Case ◽  
Worst Case Execution Time ◽  
Time Calculation ◽  
Multiple Threads ◽  
Time Systems

Worst-case execution time (WCET) is an important metric in real-time systems that helps in energy usage modeling and predefined execution time requirement evaluation. While basic timing analysis relies on execution path identification and its length evaluation, multi-thread code with critical section usage brings additional complications and requires analysis of resource-waiting time estimation. In this paper, we solve a problem of worst-case execution time overestimation reduction in situations when multiple threads are executing loops with the same critical section usage in each iteration. The experiment showed the worst-case execution time does not take into account the proportion between computational and critical sections; therefore, we proposed a new worst-case execution time calculation model to reduce the overestimation. The proposed model results prove to reduce the overestimation on average by half in comparison to the theoretical model. Therefore, this leads to more accurate execution time and energy consumption estimation.

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