{"title":"Scheduling adaptive tasks in real-time systems","authors":"Kai Wang, Tein-Hsiang Lin","doi":"10.1109/REAL.1994.342715","DOIUrl":"https://doi.org/10.1109/REAL.1994.342715","url":null,"abstract":"In a real-time system, a repetitive task can be scheduled as a periodic task or an adaptive task to meet its timing requirement. For a periodic task, the deadline is always one period interval from the ready time and the current deadline will become the ready time for the next task instance. Whereas for an adaptive task, the deadline is set to one period interval from the completion of the previous task instance and the ready time can be set anywhere before the deadline. Periodic task scheduling has be researched extensively in the past. The authors study the scheduling of adaptive tasks. This study is motivated by the study of resource allocation for a radar system with adaptive sensors, where the resources would be used more efficiently if the sensor tasks are scheduled as adaptive tasks.<<ETX>>","PeriodicalId":374952,"journal":{"name":"1994 Proceedings Real-Time Systems Symposium","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131085024","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}
{"title":"Flexible real-time SQL transactions","authors":"P. Fortier, V. Wolfe, J. Prichard","doi":"10.1109/REAL.1994.342707","DOIUrl":"https://doi.org/10.1109/REAL.1994.342707","url":null,"abstract":"Presents flexible transaction structuring capabilities that allow related ACID properties (atomicity, consistency, isolation and durability) for better support of real-time transactions. The specification of these flexible transaction structures is demonstrated through proposed extensions to the standard SQL database language.<<ETX>>","PeriodicalId":374952,"journal":{"name":"1994 Proceedings Real-Time Systems Symposium","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126506399","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}
{"title":"Busy-idle profiles and compact task graphs: compile-time support for interleaved and overlapped scheduling of real-time tasks","authors":"Rajiv Gupta, Madalene Spezialetti","doi":"10.1109/REAL.1994.342727","DOIUrl":"https://doi.org/10.1109/REAL.1994.342727","url":null,"abstract":"A new task graph representation, namely the compact task graph (CTG) is developed to aid in the scheduling of a set of communicating periodic real-time tasks. This representation exposes the potential for parallelism across tasks as well as the idle times that may be encountered within a task. Therefore using a CTG a real-time scheduler can generate schedules that are able to meet deadlines by interleaving the execution of tasks on a single processor and/or overlapping the execution of tasks on multiple processors. The construction of a CTG is based upon the busy-idle execution profiles for the tasks generated by the compiler. The profiles are computed assuming that sufficient resources are available for parallel execution of all tasks. Thus, they expose all opportunities for overlapped and interleaved execution. The compiler analyzes the profiles to identify useful opportunities for interleaving and expresses them in the CTG without explicitly partitioning the tasks. The CTG is powerful because it expresses schedules that are not expressed by existing approaches for constructing task graphs. Schedules can be generated efficiently since a CTG's construction does not require the splitting of tasks. We also demonstrate the usefulness of our techniques by developing an approach for non-intrusive monitoring of real-time tasks.<<ETX>>","PeriodicalId":374952,"journal":{"name":"1994 Proceedings Real-Time Systems Symposium","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132027860","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}
Sung-Soo Lim, Young Hyun Bae, Gyu Tae Jang, Byung-Do Rhee, S. Min, C. Park, Heonshik Shin, Kunsoo Park, Chong-Sang Kim
{"title":"An accurate worst case timing analysis technique for RISC processors","authors":"Sung-Soo Lim, Young Hyun Bae, Gyu Tae Jang, Byung-Do Rhee, S. Min, C. Park, Heonshik Shin, Kunsoo Park, Chong-Sang Kim","doi":"10.1109/REAL.1994.342726","DOIUrl":"https://doi.org/10.1109/REAL.1994.342726","url":null,"abstract":"An accurate and safe estimation of a task's worst case execution time (WCET) is crucial for reasoning about the timing properties of real-time systems. In RISC processors, the execution time of a program construct (e.g., a statement) is affected by various factors such as cache hits/misses and pipeline hazards, and these factors impose serious problems in analyzing the WCETs of tasks. To analyze the timing effects of RISC's pipelined execution and cache memory, this paper proposes extensions of the original timing schema (Shaw, 1989) where the timing information associated with each program construct is a simple time-bound. We associate with each program construct what we call a WCTA (Worst Case Timing Abstraction), which contains detailed timing information of every execution path that might be the worst case execution path of the program construct. This extension leads to a revised timing schema that is similar to the original timing schema except that concatenation and pruning operations on WCTAs are newly defined to replace the add and max operations on time-bounds in the original timing schema. Our revised timing schema accurately accounts for the timing effects of pipelined execution and cache memory not only within but also across program constructs. This paper also reports on preliminary results of WCET analyses for a pipelined processor. Our results show that up to 50% tighter WCET bounds can be obtained by using the revised timing schema.<<ETX>>","PeriodicalId":374952,"journal":{"name":"1994 Proceedings Real-Time Systems Symposium","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115139938","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}
T. Carpenter, K. Driscoll, K. Hoyme, Jim Carciofini
{"title":"ARINC 659 scheduling: problem definition","authors":"T. Carpenter, K. Driscoll, K. Hoyme, Jim Carciofini","doi":"10.1109/REAL.1994.342719","DOIUrl":"https://doi.org/10.1109/REAL.1994.342719","url":null,"abstract":"Honeywell is completing integration of the new Boeing 777 integrated Airplane Information Management System (AIMS). AIMS functions range from hard real-time to non-real-time, include flight-critical and non-essential functions, and must all reside on the same distributed multiprocessor system. This system, based on Aeronautical Radio Inc's ARINC 659 specification, allows for high resource utilization while providing strict partitioning and provable performance via pre-scheduling of processing and communication resources. Such scheduling presents significant theoretical and practical problems. This paper describes these scheduling requirements with the intent of providing the research community with practical bounds for problem definition.<<ETX>>","PeriodicalId":374952,"journal":{"name":"1994 Proceedings Real-Time Systems Symposium","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125180642","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}
{"title":"Bounding worst-case instruction cache performance","authors":"R. Arnold, F. Mueller, D. Whalley, M. Harmon","doi":"10.1109/REAL.1994.342718","DOIUrl":"https://doi.org/10.1109/REAL.1994.342718","url":null,"abstract":"The use of caches poses a difficult tradeoff for architects of real-time systems. While caches provide significant performance advantages, they have also been viewed as inherently unpredictable, since the behavior of a cache reference depends upon the history of the previous references. The use of caches is only suitable for real-time systems if a reasonably tight bound on the performance of programs using cache memory can be predicted. This paper describes an approach for bounding the worst-case instruction cache performance of large code segments. First, a new method called static cache simulation is used to analyze a program's control flow to statically categorize the caching behavior of each instruction. A timing analyzer, which uses the categorization information, then estimates the worst-case instruction cache performance for each loop and function in the program.<<ETX>>","PeriodicalId":374952,"journal":{"name":"1994 Proceedings Real-Time Systems Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130323513","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}
{"title":"Supporting real-time traffic on Ethernet","authors":"C. Venkatramani, T. Chiueh","doi":"10.1109/REAL.1994.342706","DOIUrl":"https://doi.org/10.1109/REAL.1994.342706","url":null,"abstract":"Ethernet has been the dominant local area network architecture in the last decade, and we believe that it will continue to be so because of its cost-effectiveness and the availability of higher-bandwidth Ethernets. We propose and evaluate a software-based protocol called RETHER (Real-time ETHERnet) that provider real-time performance guarantees to multimedia applications without modifying existing Ethernet hardware. RETHER features a hybrid mode of operation to reduce the performance impact on non-real-time network packets, a race-condition-free distributed admission control mechanism, and an efficient token-passing scheme that protects the network against token loss due to node failures.<<ETX>>","PeriodicalId":374952,"journal":{"name":"1994 Proceedings Real-Time Systems Symposium","volume":"141 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123148851","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}
{"title":"A solution to an automotive control system benchmark","authors":"H. Kopetz","doi":"10.1109/REAL.1994.342721","DOIUrl":"https://doi.org/10.1109/REAL.1994.342721","url":null,"abstract":"The Society of Automotive Engineers (SAE) has recently published a set of requirements and a control benchmark which is able to compare the effectiveness of new protocol proposals for safety-critical automotive systems. This paper presents a solution to this benchmark problem that is based on the Time Triggered Protocol (TTP). TTP integrates all services required for the implementation of fault-tolerant hard real-time systems, while trying to minimize the bandwidth requirements.<<ETX>>","PeriodicalId":374952,"journal":{"name":"1994 Proceedings Real-Time Systems Symposium","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114679164","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}
Daniel I. Katcher, Kevin A. Kettler, J. Strosnider
{"title":"Modeling DSP operating systems for multimedia applications","authors":"Daniel I. Katcher, Kevin A. Kettler, J. Strosnider","doi":"10.1109/REAL.1994.342705","DOIUrl":"https://doi.org/10.1109/REAL.1994.342705","url":null,"abstract":"Real-time scheduling theory attempts to guarantee that a real-time task set will always meet its deadlines. Real-time systems are typically implemented via real-time operating systems (RTOSs). However, there currently exists a wide gap between real-time scheduling theory and the reality of RTOS implementation. Bridging the gap requires effort on two fronts. First, real-time scheduling theory must be extended such that implementation realities may be correctly incorporated. Second, the high level of sophistication required to apply real-time scheduling theory to RTOSs bars practitioners from creating scheduling (timing) models of their operating systems. This paper summarizes recent work on developing an engineering methodology that allows novice users and developers to accurately model and evaluate RTOSs. Specifically, we recount the experiences of a CMU undergraduate class's experience in modeling and analyzing three commercial Digital Signal Processor (DSP) operating systems.<<ETX>>","PeriodicalId":374952,"journal":{"name":"1994 Proceedings Real-Time Systems Symposium","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114697885","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}
{"title":"Algorithms for scheduling hard aperiodic tasks in fixed-priority systems using slack stealing","authors":"S. R. Thuel, J. Lehoczky","doi":"10.1109/REAL.1994.342733","DOIUrl":"https://doi.org/10.1109/REAL.1994.342733","url":null,"abstract":"This paper discusses the problem of jointly scheduling hard deadline periodic tasks and hard deadline aperiodic tasks using fixed priority methods. The approach is based on the slack stealing algorithm developed by the authors, and it assumes that the periodic deadlines must all be met. The paper develops a hard aperiodic acceptance test algorithm for guaranteeing tasks at any priority level, and it corrects an error in the original guarantee algorithm presented in Ramos-Thuel and Lehoczky (1993). It is shown that there is no optimal priority assignment for hard aperiodic task, but guidelines are given for choosing a good priority assignment.<<ETX>>","PeriodicalId":374952,"journal":{"name":"1994 Proceedings Real-Time Systems Symposium","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125872626","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}
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