| 1. |
- Betts, Adam, et al.
(författare)
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Identifying irreducible loops in the Instrumentation Point Graph
- 2011
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Ingår i: Journal of systems architecture. - : Elsevier BV. - 1383-7621 .- 1873-6165. ; 57:7, s. 720-733
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Tidskriftsartikel (refereegranskat)abstract
- The Instrumentation Point Graph (IPG) is a program model whose primary usage is within hybrid measurement-based frameworks that compute Worst-Case Execution Time (WCET) estimates. The IPG represents the transitions between instrumentation points (Ipoints) that are inserted into the program to collect measurements at run time. However, uncontrolled Ipoint placement often causes the resultant IPG to contain unstructured (i.e. irreducible) loops, potentially compromising the safety of WCET estimates unless the hierarchical containment among IPG loops can be correctly identified. The contributions of this paper are fourfold: (1) we show that the IPG is more susceptible to irreducibility even when the program itself is well structured; (2) we demonstrate that state-of-the-art loop detection algorithms, designed specifically to handle irreducible loops, generally fail to construct the correct hierarchical relationship between IPG loops; (3) we present an algorithm that identifies arbitrary irreducible loops in the IPG during its construction from another graph-based model, an extended type of Control Flow Graph (CFG) called the CFG(+); (4) we show how the structural relation between the IPG and the CFG(+) allows loop bounds obtained through static analysis to be transferred onto the IPG. (C) 2011 Elsevier B.V. All rights reserved.
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| 2. |
- Gustafsson, Jan, et al.
(författare)
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ALL-TIMES - a European Project on Integrating Timing Technology
- 2008
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Ingår i: Communications in Computer and Information Science, Volume 17. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 9783540884781 ; , s. 445-459
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Konferensbidrag (refereegranskat)abstract
- ALL-TIMES is a research project within the EC 7th Framework Programme. The project concerns embedded systems that are subject to safety, availability, reliability, and performance requirements. Increasingly, these requirements relate to correct timing. Consequently, the need for appropriate timing analysis methods and tools is growing rapidly. An increasing number of sophisticated and technically mature timing analysis tools and methods are becoming available commercially and in academia. However, tools and methods have historically been developed in isolation, and the potential users are missing a process-related and continuous tool- and methodology-support. Due to this fragmentation, the timing analysis tool landscape does not yet fully exploit its potential.The ALL-TIMES project aims at: combining independent research results into a consistent methodology, integrating available timing tools into a single framework, and developing new timing analysis methods and tools where appropriate.ALL-TIMES will enable interoperability of the various tools from leading commercial vendors and universities alike, and develop integrated tool chains using as well as creating open tool frameworks and interfaces. In order to evaluate the tool integrations, a number of industrial case studies will be performed.This paper describes the aims of the ALL-TIMES project, the partners, and the planned work.
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| 3. |
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| 4. |
- Wilhelm, Reinhard, et al.
(författare)
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The worst-case execution-time problem—overview of methods and survey of tools
- 2008
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Ingår i: ACM Transactions on Embedded Computing Systems. - : Association for Computing Machinery (ACM). - 1539-9087 .- 1558-3465. ; 7:3, s. article nr: 36-
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Tidskriftsartikel (refereegranskat)abstract
- The determination of upper bounds on execution times, commonly called worst-case execution times (WCETs), is a necessary step in the development and validation process for hard real-time systems. This problem is hard if the underlying processor architecture has components, such as caches, pipelines, branch prediction, and other speculative components. This article describes different approaches to this problem and surveys several commercially available tools(1) and research prototypes.
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