2016 28th Euromicro Conference on Real-Time Systems (ECRTS)最新文献_第2页

A Framework for the Derivation of WCET Analyses for Multi-core Processors 多核处理器WCET分析的推导框架

2016 28th Euromicro Conference on Real-Time Systems (ECRTS) Pub Date : 2016-07-05 DOI: 10.1109/ECRTS.2016.19

M. Jacobs, S. Hahn, Sebastian Hack

{"title":"A Framework for the Derivation of WCET Analyses for Multi-core Processors","authors":"M. Jacobs, S. Hahn, Sebastian Hack","doi":"10.1109/ECRTS.2016.19","DOIUrl":"https://doi.org/10.1109/ECRTS.2016.19","url":null,"abstract":"Multi-core processors share common hardware resources between several processor cores. As a consequence, the performance of one processor core is influenced by the programs executed on the concurrent cores. We refer to this phenomenon as shared-resource interference. An explicit consideration of all such interference effects is in general combinatorially infeasible. This makes a precise worst-case execution time (WCET) analysis for multi-core processors challenging. In order to reduce the complexity, WCET analyses for multi-core processors coarsely approximate the behavior of the considered applications. However, current approaches are only applicable to rather restricted classes of hardware platforms. We propose a framework for the derivation of WCET analyses for multi-core processors. It relaxes the restricting assumptions that existing approaches are based on. The derivation starts from a WCET analysis that makes maximally pessimistic assumptions about the shared-resource interference. More precise interference bounds for the concrete system are subsequently lifted to the approximation of the analysis. The lifted bounds are finally incorporated in the analysis in order to model the interference in a more precise way.","PeriodicalId":178974,"journal":{"name":"2016 28th Euromicro Conference on Real-Time Systems (ECRTS)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124891400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Minimizing DRAM Rank Switching Overhead for Improved Timing Bounds and Performance 最小化DRAM等级交换开销以改善时序边界和性能

2016 28th Euromicro Conference on Real-Time Systems (ECRTS) Pub Date : 2016-07-05 DOI: 10.1109/ECRTS.2016.8

L. Ecco, Adam Kostrzewa, R. Ernst

引用次数: 15

Multiprocessor Real-Time Scheduling with Hierarchical Processor Affinities 具有分层处理器亲和性的多处理器实时调度

2016 28th Euromicro Conference on Real-Time Systems (ECRTS) Pub Date : 2016-07-05 DOI: 10.1109/ECRTS.2016.24

V. Bonifaci, Björn B. Brandenburg, Gianlorenzo D'angelo, A. Marchetti-Spaccamela

{"title":"Multiprocessor Real-Time Scheduling with Hierarchical Processor Affinities","authors":"V. Bonifaci, Björn B. Brandenburg, Gianlorenzo D'angelo, A. Marchetti-Spaccamela","doi":"10.1109/ECRTS.2016.24","DOIUrl":"https://doi.org/10.1109/ECRTS.2016.24","url":null,"abstract":"Many multiprocessor real-time operating systems offer the possibility to restrict the migrations of any task to a specified subset of processors by setting affinity masks. A notion of “strong arbitrary processor affinity scheduling” (strong APA scheduling) has been proposed; this notion avoids schedulability losses due to overly simple implementations of processor affinities. Due to potential overheads, strong APA has not been implemented so far in a real-time operating system. We show that, in the special but highly relevant case of hierarchical processor affinities (HPA), strong APA scheduling can be implemented with a vastly improved runtime complexity. In particular, we present a strong HPA scheduler with a runtime complexity of O(m) per task arrival and O(log n+m2) per task departure, where mis the number of processors and n is the number of tasks, thus improving on the previous bounds of O(m2) and O(mn). The improved runtime algorithms allowed us to implement support for strong hierarchical processor affinities in LITMUSRT. We benchmarked this implementation on a 24-core platform and observed nonnegligible, but still viable runtime overheads. Additionally, in the case of a bilevel affinity hierarchy and when job priorities are based on deadlines, we argue that the performance of our strong HPA scheduler, HPA-EDF, can be related to system optimality in the following way: any collection of jobs that is schedulable (under any policy) on m unit-speed processors subject to hierarchical affinity constraints is correctly scheduled by HPA-EDF on m processors of speed 2.415.","PeriodicalId":178974,"journal":{"name":"2016 28th Euromicro Conference on Real-Time Systems (ECRTS)","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131959434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

Schedulability Analysis of Synchronous Digraph Real-Time Tasks 同步有向图实时任务可调度性分析

2016 28th Euromicro Conference on Real-Time Systems (ECRTS) Pub Date : 2016-07-01 DOI: 10.1109/ECRTS.2016.17

M. Mohaqeqi, Jakaria Abdullah, Nan Guan, W. Yi

引用次数: 16

Sleep Scheduling for Energy-Savings in Multi-core Processors 多核处理器的节能睡眠调度

2016 28th Euromicro Conference on Real-Time Systems (ECRTS) Pub Date : 2016-07-01 DOI: 10.1109/ECRTS.2016.16

Sandeep M. D'Souza, Anand Bhat, R. Rajkumar

{"title":"Sleep Scheduling for Energy-Savings in Multi-core Processors","authors":"Sandeep M. D'Souza, Anand Bhat, R. Rajkumar","doi":"10.1109/ECRTS.2016.16","DOIUrl":"https://doi.org/10.1109/ECRTS.2016.16","url":null,"abstract":"As transistor geometries get smaller, static leakage power dominates the power consumption in modern processors. This phenomenon diminishes the ability of frequency scaling-based techniques to save energy. Modern processors also provide sleep states which minimize leakage power by gating portions of the processor and/or the system clock. This paper presents partitioned fixed-priority scheduling solutions for utilizing these sleep states to efficiently schedule periodic real-time tasks, and maximize energy savings on multi-core processors. The techniques presented rely on an Enhanced Version of Energy-Saving Rate-Harmonized Scheduling (ES-RHS), and our newly proposed Energy-Saving Rate-Monotonic Scheduling (ES-RMS) policy to maximize the time the processor spends in the lowest-power deep sleep state. In some modern multi-core processors, all cores need to transition synchronously into deep sleep. For this class of processors, we present a partitioning technique called Max-SyncSleep which utilizes a priori task information, to maximize the synchronous deep sleep duration across all processing cores. The performance of Max-SyncSleep is compared to the classical Worst-Fit Decreasing load balancing heuristic. We also illustrate the benefits of using ES-RMS over ES-RHS for this class of processors. For processors which allow cores to individually transition into deep sleep, we prove that, while utilizing ES-RHS on each core, any feasible partition can optimally utilize all of the processor's idle durations to put it into deep sleep. Experimental evaluations indicate that the proposed techniques can provide significant energy savings.","PeriodicalId":178974,"journal":{"name":"2016 28th Euromicro Conference on Real-Time Systems (ECRTS)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123976946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Contention-Free Execution of Automotive Applications on a Clustered Many-Core Platform 集群多核平台上汽车应用程序的无争用执行

2016 28th Euromicro Conference on Real-Time Systems (ECRTS) Pub Date : 2016-07-01 DOI: 10.1109/ECRTS.2016.14

Matthias Becker, D. Dasari, Borislav Nikolic, B. Akesson, Vincent Nélis, Thomas Nolte

{"title":"Contention-Free Execution of Automotive Applications on a Clustered Many-Core Platform","authors":"Matthias Becker, D. Dasari, Borislav Nikolic, B. Akesson, Vincent Nélis, Thomas Nolte","doi":"10.1109/ECRTS.2016.14","DOIUrl":"https://doi.org/10.1109/ECRTS.2016.14","url":null,"abstract":"Next generations of compute-intensive real-time applications in automotive systems will require more powerful computing platforms. One promising power-efficient solution for such applications is to use clustered many-core architectures. However, ensuring that real-time requirements are satisfied in the presence of contention in shared resources, such as memories, remains an open issue. This work presents a novel contention-free execution framework to execute automotive applications on such platforms. Privatization of memory banks together with defined access phases to shared memory resources is the backbone of the framework. An Integer Linear Programming (ILP) formulation is presented to find the optimal time-triggered schedule for the on-core execution as well as for the access to shared memory. Additionally a heuristic solution is presented that generates the schedule in a fraction of the time required by the ILP. Extensive evaluations show that the proposed heuristic performs only 0.5% away from the optimal solution while it outperforms a baseline heuristic by 67%. The applicability of the approach to industrially sized problems is demonstrated in a case study of a software for Engine Management Systems.","PeriodicalId":178974,"journal":{"name":"2016 28th Euromicro Conference on Real-Time Systems (ECRTS)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126806237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 83

Non-work-conserving Non-preemptive Scheduling: Motivations, Challenges, and Potential Solutions 非节省工作的非抢占式调度:动机、挑战和潜在的解决方案

2016 28th Euromicro Conference on Real-Time Systems (ECRTS) Pub Date : 2016-07-01 DOI: 10.1109/ECRTS.2016.11

M. Nasri, G. Fohler

{"title":"Non-work-conserving Non-preemptive Scheduling: Motivations, Challenges, and Potential Solutions","authors":"M. Nasri, G. Fohler","doi":"10.1109/ECRTS.2016.11","DOIUrl":"https://doi.org/10.1109/ECRTS.2016.11","url":null,"abstract":"In many real-time systems, preemption is either impossible or prohibitively expensive. The problem of scheduling non-preemptive periodic tasks with known release offsets is known to be NP-Hard. In this paper, we investigate the existing non-preemptive scheduling algorithms in both categories of work-conserving and non-work-conserving algorithms, where in the former, the processing resource is not allowed to be idle as long as there is an unfinished job in the system. While describing the advantages and weaknesses of the existing scheduling solutions we show that using online non-work-conserving algorithms it is possible to schedule more task sets. In our work, we discuss the challenges to design the idle-time insertion policy (IIP) which can be combined with the existing scheduling policies such as the earliest deadline first (EDF), rate monotonic (RM), etc. Further we present a tighter necessary condition for schedulability of non-preemptive tasks. We also provide an IIP for EDF based on looking into a number of jobs in future. Through the experiments we show that the our IIP for EDF significantly increases the schedulability of non-preemptive tasks, particularly in periodic task sets. While our schedulability ratio is more than 80%, the state of the art work-conserving algorithms are about 15%.","PeriodicalId":178974,"journal":{"name":"2016 28th Euromicro Conference on Real-Time Systems (ECRTS)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134436498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 21

PROSA: A Case for Readable Mechanized Schedulability Analysis PROSA:一个可读的机械化可调度性分析案例

2016 28th Euromicro Conference on Real-Time Systems (ECRTS) Pub Date : 2016-07-01 DOI: 10.1109/ECRTS.2016.28

Felipe Cerqueira, Felix Stutz, Björn B. Brandenburg

引用次数: 41

Extreme Value Theory for Estimating Task Execution Time Bounds: A Careful Look 估计任务执行时间界限的极值理论:仔细观察

2016 28th Euromicro Conference on Real-Time Systems (ECRTS) Pub Date : 2016-07-01 DOI: 10.1109/ECRTS.2016.20

George Lima, D. Dias, E. Barros

{"title":"Extreme Value Theory for Estimating Task Execution Time Bounds: A Careful Look","authors":"George Lima, D. Dias, E. Barros","doi":"10.1109/ECRTS.2016.20","DOIUrl":"https://doi.org/10.1109/ECRTS.2016.20","url":null,"abstract":"Extreme Value Theory (EVT) is a powerful statistical framework for estimating maximum values of random variables and has recently been applied for deriving probabilistic bounds on task execution times (pWCET). Task execution time data are collected from measurements and the maximum measured values are fit to an extreme value model. In this paper we provide a careful study on the applicability and effectiveness of EVT in this application field. The study is based on extensive experiments for which we have designed an embedded platform equipped with random cache of configurable sizes. Based on evidences of the experiments, we provide the following contributions: we give a new definition of pWCET that conforms with the fact that pWCET estimates depend on input data distribution used during analysis, we show that using the Generalized Extreme Value (GEV) distribution is necessary since the more restrictive modeling, based on the Gumbel distribution, may yield unsafe or over-estimated values of pWCET, we confirm that hardware randomization favors the applicability of EVT, although it does not ensure it since the distribution of maxima for execution time data are not guaranteed to be analyzable via EVT.","PeriodicalId":178974,"journal":{"name":"2016 28th Euromicro Conference on Real-Time Systems (ECRTS)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121996064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 52

Multiprocessor Real-Time Locking Protocols for Replicated Resources 复制资源的多处理器实时锁定协议

2016 28th Euromicro Conference on Real-Time Systems (ECRTS) Pub Date : 2016-07-01 DOI: 10.1109/ECRTS.2016.29

Catherine E. Nemitz, Kecheng Yang, Ming Yang, Pontus Ekberg, James H. Anderson

引用次数: 12