Proceedings 20th IEEE Real-Time Systems Symposium (Cat. No.99CB37054)最新文献

{"title":"Deriving deadlines and periods for real-time update transactions","authors":"Ming Xiong, K. Ramamritham","doi":"10.1109/REAL.1999.818826","DOIUrl":"https://doi.org/10.1109/REAL.1999.818826","url":null,"abstract":"Typically, temporal validity of real-time data is maintained by periodic update transactions. In this paper we examine the problem of period and deadline assignment for these update transactions such that (1) these transactions can be guaranteed to complete by their deadlines and (2) the imposed workload is minimized. To this end, we propose a novel approach, named More-Less principle. By applying this principle, updates occur with a period which is more than the period obtained through traditional approaches but with a deadline which is less than the traditional period. We show that the More-Less principle is better than existing approaches in terms of schedulability and the imposed load. We examine the issue of determining the assignment order in which transactions must be considered for period and deadline assignment so that the resulting workloads can be minimized. To this end, the More-Less principle is first examined in a restricted case where the Shortest Validity First (SVF) order is shown to be an optimal solution. We then relax some of the restrictions and show that SVF is an approximate solution which results in workloads that are close to the optimal solution. Our analysis and experiments show that the More-Less principle is an effective design principle that can provide better schedulability and reduce update transaction workload while guaranteeing data validity constraints.","PeriodicalId":160347,"journal":{"name":"Proceedings 20th IEEE Real-Time Systems Symposium (Cat. No.99CB37054)","volume":"22 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131993001","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 scalable solution to the multi-resource QoS problem","authors":"Chen Lee, J. Lehoczky, D. Siewiorek, R. Rajkumar, Jeffery P. Hansen","doi":"10.1109/REAL.1999.818859","DOIUrl":"https://doi.org/10.1109/REAL.1999.818859","url":null,"abstract":"The problem of maximizing system utility by allocating a single finite resource to satisfy discrete Quality of Service (QoS) requirements of multiple applications along multiple QoS dimensions was studied previously. In this paper we consider the more complex problem of apportioning multiple finite resources to satisfy the QoS needs of multiple applications along multiple QoS dimensions. In other words, each application, such as video-conferencing, needs multiple resources to satisfy its QoS requirements. We evaluate and compare three strategies to solve this provably NP-hard problem. We show that dynamic programming and mixed integer programming compute optimal solutions to this problem but exhibit very long running times. We then adapt the mixed integer programming problem to yield near-optimal results with smaller running times. Finally, we present an approximation algorithm based on a local search technique that is less than 5% away from the optimal solution but which is more than two orders of magnitude faster. Perhaps more significantly, the local search technique turns out to be very scalable and robust as the number of resources required by each application increases.","PeriodicalId":160347,"journal":{"name":"Proceedings 20th IEEE Real-Time Systems Symposium (Cat. No.99CB37054)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129565131","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":"Hierarchical scheduling of periodic messages in open system","authors":"L. Y. Zhang, J. Liu, Z. Deng, I. Philp","doi":"10.1109/REAL.1999.818862","DOIUrl":"https://doi.org/10.1109/REAL.1999.818862","url":null,"abstract":"This paper describes a hierarchical scheme for scheduling periodic messages of distributed real-time applications in a cluster of PCs connected by a Myrinet. The scheme allows the developer of each real-time application to validate the schedulability of the application as if it were running alone on slower dedicated processors and network. A simple acceptance test is provided. According to the test, the operating system can determine whether to admit a new real-time system application into a system without having to perform detailed global schedulability analysis. Simulation results show that the hierarchical scheduling scheme outperforms the corresponding one-level heuristic algorithms. An open system prototype on a Myrinet cluster PCs running Windows NT uses this hierarchical scheme.","PeriodicalId":160347,"journal":{"name":"Proceedings 20th IEEE Real-Time Systems Symposium (Cat. No.99CB37054)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129908823","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":"QoS provisioning with qContracts in web and multimedia servers","authors":"T. Abdelzaher, K. Shin","doi":"10.1109/REAL.1999.818827","DOIUrl":"https://doi.org/10.1109/REAL.1999.818827","url":null,"abstract":"The advent of performance-critical services such as online brokerage and e-commerce, as well as QoS-sensitive services such as streaming multimedia, makes existing FIFO servers incapable of meeting application QoS requirements. Re-designing server code to support QoS provisioning, on the other hand, is costly and time-consuming. To remedy this problem, we propose a new QoS-provisioning approach that does not require modification of server and QoS code. We develop a middleware, called qContracts, that can be transparently interposed between the server process and the operating system to achieve performance differentiation and soft QoS guarantees. The middleware enables reuse of existing legacy software in QoS-sensitive contexts, and off-loads QoS management concerns from future real-time service programmers. As an example, we show how the Apache web server is endowed with QoS support using qContracts on UNIX. Experimental results show the efficacy of the middleware in achieving the contracted QoS, while imposing less than 1% overhead.","PeriodicalId":160347,"journal":{"name":"Proceedings 20th IEEE Real-Time Systems Symposium (Cat. No.99CB37054)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131883773","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":"Parallel switching in connection-oriented networks","authors":"James H. Anderson, Sanjoy Baruah, K. Jeffay","doi":"10.1109/REAL.1999.818843","DOIUrl":"https://doi.org/10.1109/REAL.1999.818843","url":null,"abstract":"Packet switching in connection-oriented networks that may have multiple parallel links between pairs of switches is considered. An efficient packet scheduling algorithm that guarantees a deterministic quality of service to connections with real time constraints is proposed; this algorithm is a generalization of some recent multiprocessor scheduling algorithms, and offers real time performance guarantees similar to those offered by earlier fair scheduling strategies, such as Weighted Fair Queueing and proportional share schemes.","PeriodicalId":160347,"journal":{"name":"Proceedings 20th IEEE Real-Time Systems Symposium (Cat. No.99CB37054)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124343315","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":"Cooperative scheduling of multiple resources","authors":"Saowanee Saewong, R. Rajkumar","doi":"10.1109/REAL.1999.818831","DOIUrl":"https://doi.org/10.1109/REAL.1999.818831","url":null,"abstract":"Obtaining simultaneous and timely access to multiple resources is known to be an NP-complete problem. Complete resource decoupling is, therefore, often used for managing end-to-end delays in distributed real-time system where each processor is scheduled independent of the others. This decoupling approach unfortunately fails when multiple resources must be managed within a single node. Resources such as disk bandwidth and network bandwidth are available on a single node but must be managed by their host processor by means of device drivers, filesystem or protocol services. The host processor acting as a controlling resource, therefore, must play multiple roles. One, it is used by applications on that node. Two, it is used to control and manage other (time-shared) controlled resources including disk bandwidth and network bandwidth. These two roles, unfortunately can often be at odds with one another. In this paper we investigate the problem of co-scheduling controlling and controlled resources. We propose the use of a Cooperative Scheduling Server (CS S), which is a dedicated server that manages one specific controlled resource (like disk bandwidth, network bandwidth, inter-process communication, etc.) while using a controlling resource (like the processor). Two core ideas underlie our approach. First, a single (aperiodic) server is created on a controlling resource (such as a CPU) to handle all local requests for a controlled resource (such as disk bandwidth). This implies that conjuctive admission control must be carried out on both the controlling and controlled resources. Secondly, timing constraints at the application level are partitioned into multiple stages, each of which will be guaranteed to complete on a particular resource. RTFS is a real-time filesystem that provides disk bandwidth guarantees under light CPU loads. With a cooperative scheduling server (FS-CSS) for this disk-based filesystem, disk bandwidth guarantees can be obtained under both heavy CPU and disk workloads. We describe the design and implementation of FS-CSS for providing disk bandwidth guarantees. We conclude with a detailed performance evaluation of FS-CSS.","PeriodicalId":160347,"journal":{"name":"Proceedings 20th IEEE Real-Time Systems Symposium (Cat. No.99CB37054)","volume":"13 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120874867","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":"HoneyWEB: embedded web-based control applications","authors":"Christiane Iaccarino, Meridith A. Sigel, Ralph E. Taylor, David Perozzi, A. Staikos, Patricia Morreale","doi":"10.1109/REAL.1999.818845","DOIUrl":"https://doi.org/10.1109/REAL.1999.818845","url":null,"abstract":"High performance monitoring and control of real-time environments over the Internet is of importance to many users. The general public, as well as professionals, desires the ability to remotely acquire real-time information at their fingertips. This paper presents a smart network design for real-time data acquisition. A streamlined web server designed specifically for embedded applications produces the real-time output for a dynamic environment. This technological enhancement is significant because it can be used in conjunction with any \"smart\" device. A unique characteristic of the design presented here is its ability to easily adapt to a variety of systems/applications. In order to achieve this type of information processing, the design approach used here was required to demonstrate the following abilities: (1) operate on a small platform without the use of an OS, (2) exchange and modify real-time data over the network, and (3) demonstrate the possibility that this type of system can be used for security purposes.","PeriodicalId":160347,"journal":{"name":"Proceedings 20th IEEE Real-Time Systems Symposium (Cat. No.99CB37054)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124718909","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":"Transport of MPEG video with statistical loss and delay guarantees in ATM networks using a histogram-based source model","authors":"Seok-Kyu Kweon, K. Shin","doi":"10.1109/REAL.1999.818841","DOIUrl":"https://doi.org/10.1109/REAL.1999.818841","url":null,"abstract":"Unlike deterministic real time communication in which excessive resources may be required for absolute performance guarantees, statistical real time communication seeks to achieve both probabilistic performance guarantees and efficient resource sharing. We propose a framework for statistical real time communication in ATM networks that provides delay guaranteed transport of MPEG coded video traffic with a statistically guaranteed cell loss ratio. In order to provide delay guaranteed communication service, we employ a modified version of Traffic-Controlled Rate-Monotonic Priority Scheduling (TCRM). We multiplex a set of statistical real time channels that share: (i) similar traffic characteristics into a common channel called a macro channel, and (ii) the resources of the macro channel. Individual statistical real time channels are given timeliness and probabilistic cell loss guarantees. A macro channel is serviced by the modified TCRM which improves link utilization and makes channel management simpler. Using the analysis of an M/D/1/N queueing system, we propose a procedure for determining the transmission capacity of a macro channel needed to statistically guarantee a cell loss ratio bound. Simulation results have shown our framework to work well as compared to the other approaches. The overall cell loss ratios for multi hop statistical real time channels are shown to be smaller than the pre-determined bounds.","PeriodicalId":160347,"journal":{"name":"Proceedings 20th IEEE Real-Time Systems Symposium (Cat. No.99CB37054)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122577772","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":"Real-time garbage collection in multi-threaded systems on a single processor","authors":"Fridtjof Siebert","doi":"10.1109/REAL.1999.818854","DOIUrl":"https://doi.org/10.1109/REAL.1999.818854","url":null,"abstract":"We show the difficulties that arise for the implementation of a real-time garbage collector (GC) in a multi-threaded system. A mechanism for synchronization between threads is proposed for a single processor system. It is shown how this mechanism can be used to maintain exact information on roots, to do incremental or even constant-time root-scanning and to allow pre-emption of GC activity.","PeriodicalId":160347,"journal":{"name":"Proceedings 20th IEEE Real-Time Systems Symposium (Cat. No.99CB37054)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127741544","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":"Exploiting precedence relations in the schedulability analysis of distributed real-time systems","authors":"J. Palencia, M. G. Harbour","doi":"10.1109/REAL.1999.818860","DOIUrl":"https://doi.org/10.1109/REAL.1999.818860","url":null,"abstract":"In this paper we present improved techniques for the schedulability analysis of tasks with precedence relations in multiprocessor and distributed systems scheduled under a pre-emptive fixed priority scheduler. Recently developed techniques, based on the analysis of tasks with dynamic offsets, take into account the precedence relations between tasks only indirectly, through terms iteratively estimated from the response times of the tasks. With the techniques presented in this paper, we exploit the precedence relations in a more accurate way, and we also take advantage of the priority structure of the different tasks. These considerations permit a significant improvement of the results of the analysis applied to distributed and multiprocessor systems.","PeriodicalId":160347,"journal":{"name":"Proceedings 20th IEEE Real-Time Systems Symposium (Cat. No.99CB37054)","volume":"255 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114475150","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}