Proceedings Real-Time Systems Symposium最新文献_第2页

More optimism about real-time distributed commit processing 对实时分布式提交处理更加乐观

Proceedings Real-Time Systems Symposium Pub Date : 1997-12-03 DOI: 10.1109/REAL.1997.641275

Ramesh Gupta, J. Haritsa, K. Ramamritham

{"title":"More optimism about real-time distributed commit processing","authors":"Ramesh Gupta, J. Haritsa, K. Ramamritham","doi":"10.1109/REAL.1997.641275","DOIUrl":"https://doi.org/10.1109/REAL.1997.641275","url":null,"abstract":"In (Gupta et al., 1996), we proposed a new commit protocol, OPT, specially designed for use in distributed firm-deadline real-time database systems. OPT allows transactions to optimistically borrow uncommitted prepared data in a controlled manner. This controlled borrowing reduces the data inaccessibility and the priority inversion that is inherent in real-time commit processing. Experimental evaluations showed the new OPT protocol to be highly successful, as compared to the classical distributed commit protocols, in minimizing the number of missed transaction deadlines. In this paper, we extend and improve upon this prior work in the following ways. First, we consider parallel distributed transactions whereas the previous study was restricted to sequential transactions. Second, we evaluate the extent to which OPT's real-time performance is adversely affected by those cases where its optimism turns out to be misplaced. This is achieved by comparing OPT's performance with that of Shadow-OPT, a protocol that augments OPT with the shadow transaction approach and ensures that the right decision about access to uncommitted data is always eventually made. In all of our experiments, which considered a wide range of workloads and system configurations, the difference between OPT and Shadow-OPT never exceeded ten percent. Moreover, the difference was reduced to less than two percent when OPT was enhanced with a simple healthy lenders heuristic. Finally, we compare the performance of OPT to that of an alternative priority, inheritance-based approach to addressing priority inversion during commit processing.","PeriodicalId":231201,"journal":{"name":"Proceedings Real-Time Systems Symposium","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116489666","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: 33

Efficient verification of real-time systems: compact data structure and state-space reduction 实时系统的有效验证:紧凑的数据结构和状态空间缩减

Proceedings Real-Time Systems Symposium Pub Date : 1997-12-03 DOI: 10.1109/REAL.1997.641265

K. Larsen, F. Larsson, P. Pettersson, W. Yi

{"title":"Efficient verification of real-time systems: compact data structure and state-space reduction","authors":"K. Larsen, F. Larsson, P. Pettersson, W. Yi","doi":"10.1109/REAL.1997.641265","DOIUrl":"https://doi.org/10.1109/REAL.1997.641265","url":null,"abstract":"During the past few years, a number of verification tools have been developed for real-time systems in the framework of timed automata (e.g. KRONOS and UPPAAL). One of the major problems in applying these tools to industrial-size systems is the huge memory-usage for the exploration of the state-space of a network (or product) of timed automata, as the model-checkers must keep information on not only the control structure of the automata but also the clock values specified by clock constraints. In this paper, we present a compact data structure for representing clock constraints. The data structure is based on an O(n/sup 3/) algorithm which, given a constraint system over real-valued variables consisting of bounds on differences, constructs an equivalent system with a minimal number of constraints. In addition, we have developed an on-the-fly, reduction technique to minimize the space-usage. Based on static analysis of the control structure of a network of timed automata, we are able to compute a set of symbolic states that cover all the dynamic loops of the network in an on-the-fly searching algorithm, and thus ensure termination in reachability analysis. The two techniques and their combination have been implemented in the tool UPPAAL. Our experimental results demonstrate that the techniques result in truly significant space-reductions: for six examples from the literature, the space saving is between 75% and 94%, and in (nearly) all examples time-performance is improved. Also noteworthy is the observation that the two techniques are completely orthogonal.","PeriodicalId":231201,"journal":{"name":"Proceedings Real-Time Systems Symposium","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123723506","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: 229

On adaptive resource allocation for complex real-time applications 复杂实时应用的自适应资源分配

Proceedings Real-Time Systems Symposium Pub Date : 1997-12-03 DOI: 10.1109/REAL.1997.641293

D. Rosu, K. Schwan, S. Yalamanchili, R. Jha

引用次数: 170

Adaptive fault tolerance and graceful degradation under dynamic hard real-time scheduling 动态硬实时调度下的自适应容错与优雅退化

Proceedings Real-Time Systems Symposium Pub Date : 1997-12-03 DOI: 10.1109/REAL.1997.641271

O. González, H. Shrikumar, J. Stankovic, K. Ramamritham

{"title":"Adaptive fault tolerance and graceful degradation under dynamic hard real-time scheduling","authors":"O. González, H. Shrikumar, J. Stankovic, K. Ramamritham","doi":"10.1109/REAL.1997.641271","DOIUrl":"https://doi.org/10.1109/REAL.1997.641271","url":null,"abstract":"Static redundancy allocation is inappropriate in hard real-time systems that operate in variable and dynamic environments, (e.g., radar tracking, avionics). Adaptive fault tolerance (AFT) can assure adequate reliability of critical modules, under temporal and resource constraints, by allocating just as much redundancy to less critical modules as can be afforded thus gracefully reducing their resource requirement. We propose a mechanism for supporting adaptive fault tolerance in a real-time system. Adaptation is achieved by choosing a suitable redundancy strategy for a dynamically arriving computation to assure required reliability and to maximize the potential for fault tolerance while ensuring that deadlines are met. The proposed approach is evaluated using a real-life workload simulating radar tracking software in AWACS early warning aircraft. The results demonstrate that our technique outperforms static fault tolerance strategies in terms of tasks meeting their timing constraints. Further, we show that the gain in this timing-centric performance metric does not reduce the fault tolerance of the executing task below a predefined minimum level. Overall, the evaluation indicates that the proposed ideas result in a system that dynamically provides QoS guarantees along the fault-tolerance dimension.","PeriodicalId":231201,"journal":{"name":"Proceedings Real-Time Systems Symposium","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134240186","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: 77

Scheduling real-time applications in an open environment 在开放环境中调度实时应用程序

Proceedings Real-Time Systems Symposium Pub Date : 1997-12-03 DOI: 10.1109/REAL.1997.641292

Z. Deng, J. Liu

引用次数: 498

Response-time guarantees in ATM networks ATM网络中的响应时间保证

Proceedings Real-Time Systems Symposium Pub Date : 1997-12-03 DOI: 10.1109/REAL.1997.641289

Andreas Ermedahl, H. Hansson, Mikael Sjödin

引用次数: 52

Scalable hardware earliest-deadline-first scheduler for ATM switching networks 用于ATM交换网络的可伸缩硬件最早截止日期优先调度程序

Proceedings Real-Time Systems Symposium Pub Date : 1997-12-03 DOI: 10.1109/REAL.1997.641283

B. Kim, K. Shin

引用次数: 27

Wait-free object-sharing schemes for real-time uniprocessors and multiprocessors 实时单处理器和多处理器的无等待对象共享方案

Proceedings Real-Time Systems Symposium Pub Date : 1997-12-03 DOI: 10.1109/REAL.1997.641274

James H. Anderson, R. Jain, Srikanth Ramamurthy

引用次数: 36

Implementation and evaluation of real-time Java threads 实时Java线程的实现和评估

Proceedings Real-Time Systems Symposium Pub Date : 1997-12-03 DOI: 10.1109/REAL.1997.641279

A. Miyoshi, Takuro Kitayama, H. Tokuda

引用次数: 28

Efficient spare-resource allocation for fast restoration of real-time channels from network component failures 有效的空闲资源分配，从网络组件故障中快速恢复实时通道

Proceedings Real-Time Systems Symposium Pub Date : 1997-12-03 DOI: 10.1109/REAL.1997.641273

Seungjae Han, K. Shin

引用次数: 52