2015 27th Euromicro Conference on Real-Time Systems最新文献_第3页

Resource Efficient Isolation Mechanisms in Mixed-Criticality Scheduling 混合临界调度中的资源高效隔离机制

2015 27th Euromicro Conference on Real-Time Systems Pub Date : 2015-07-08 DOI: 10.1109/ECRTS.2015.9

Xiaozhe Gu, A. Easwaran, Kieu-My Phan, I. Shin

{"title":"Resource Efficient Isolation Mechanisms in Mixed-Criticality Scheduling","authors":"Xiaozhe Gu, A. Easwaran, Kieu-My Phan, I. Shin","doi":"10.1109/ECRTS.2015.9","DOIUrl":"https://doi.org/10.1109/ECRTS.2015.9","url":null,"abstract":"Mixed-criticality real-time scheduling has been developed to improve resource utilization while guaranteeing safe execution of critical applications. These studies use optimistic resource reservation for all the applications to improve utilization, but prioritize critical applications when the reservations become insufficient at runtime. Many of them however share an impractical assumption that all the critical applications will simultaneously demand additional resources. As a consequence, they under-utilize resources by penalizing all the low-criticality applications. In this paper we overcome this shortcoming using a novel mechanism that comprises a parameter to model the expected number of critical applications simultaneously demanding more resources, and an execution strategy based on the parameter to improve resource utilization. Since most mixed criticality systems in practice are component-based, we design our mechanism such that the component boundaries provide the isolation necessary to support the execution of low-criticality applications, and at the same time protect the critical ones. We also develop schedulability tests for the proposed mechanism under both a flat as well as a hierarchical scheduling framework. Finally, through simulations, we compare the performance of the proposed approach with existing studies in terms of schedulability and the capability to support low-criticality applications.","PeriodicalId":243434,"journal":{"name":"2015 27th Euromicro Conference on Real-Time Systems","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131136509","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: 48

Schedulability and optimization analysis for non-preemptive static priority scheduling based on task utilization and blocking factors 基于任务利用率和阻塞因素的非抢占式静态优先级调度可调度性及优化分析

2015 27th Euromicro Conference on Real-Time Systems Pub Date : 2015-07-08 DOI: 10.1109/ECRTS.2015.16

G. V. D. Brüggen, Jian-Jia Chen, Wen-Hung Huang

{"title":"Schedulability and optimization analysis for non-preemptive static priority scheduling based on task utilization and blocking factors","authors":"G. V. D. Brüggen, Jian-Jia Chen, Wen-Hung Huang","doi":"10.1109/ECRTS.2015.16","DOIUrl":"https://doi.org/10.1109/ECRTS.2015.16","url":null,"abstract":"For real time task sets, allowing preemption is often considered to be important to ensure the schedulability, as it allows high-priority tasks to be allocated to the processor nearly immediately. However, preemptive scheduling also introduces some additional overhead and may not be allowed for some hardware components, which motivates the needs of non-preemptive or limited-preemptive scheduling. We present a safe sufficient schedulability test for non-preemptive (NP) fixed priority scheduling that can verify the schedulability for Deadline Monotonic (DM-NP) and Rate Monotonic (RM-NP) scheduling in linear time, if task orders according to priority and period are given. This test leads to a better upper bound on the speedup factor for DM-NP and RM-NP in comparison to Earliest Deadline First (EDF-NP) than previously known, closing the gab between lower and upper bound. We improve our test, resulting in interesting properties of the blocking time that allow to determine schedulability by only considering the schedulability of the preemptive case if some conditions are met. Furthermore, we present a utilization bound for RM-NP, based on the ratio γ > 0 of the upper bound of the maximum blocking time to the execution time, significantly improving previous results.","PeriodicalId":243434,"journal":{"name":"2015 27th Euromicro Conference on Real-Time Systems","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129272165","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

Hybrid EDF Packet Scheduling for Real-Time Distributed Systems 实时分布式系统的混合EDF包调度

2015 27th Euromicro Conference on Real-Time Systems Pub Date : 2015-07-01 DOI: 10.1109/ECRTS.2015.11

Tao Qian, F. Mueller, Yufeng Xin

{"title":"Hybrid EDF Packet Scheduling for Real-Time Distributed Systems","authors":"Tao Qian, F. Mueller, Yufeng Xin","doi":"10.1109/ECRTS.2015.11","DOIUrl":"https://doi.org/10.1109/ECRTS.2015.11","url":null,"abstract":"When multiple computational resource elements collaborate to handle events in a cyber-physical system, scheduling algorithms on these resource elements and the communication delay between them contribute to the overall system utilization and schedulability. Employing earliest deadline first (EDF) scheduling in real-time cyber-physical systems has many challenges. First, the network layer of a resource has to interrupt and notify the scheduler about the deadlines of arrived messages. The randomness of interruption makes context switch costs unpredictable. Second, lack of globally synchronized clocks across resources renders event deadlines derived from local clocks and piggybacked in messages meaningless. Third, communication delay variances in a network increase the unpredictability of the system, e.g., When multiple resources transmit message bursts simultaneously. We address these challenges in this work. First, we combine EDF scheduling with periodic message transmission tasks. Then, we implement an EDF-based packet scheduler, which transmits packets considering event deadlines. Third, we employ bandwidth limitations on the transmission links of resources to decrease network contention and network delay variance. We have implemented our hybrid EDF scheduler in a real-time distributed storage system. We evaluate it on a cluster of nodes in a switched network environment resembling a distributed cyber-physical system to demonstrate the real-time capability of our scheduler.","PeriodicalId":243434,"journal":{"name":"2015 27th Euromicro Conference on Real-Time Systems","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114225401","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: 10

The Global EDF Scheduling of Systems of Conditional Sporadic DAG Tasks 条件零星DAG任务系统的全局EDF调度

2015 27th Euromicro Conference on Real-Time Systems Pub Date : 2015-07-01 DOI: 10.1109/ECRTS.2015.27

Sanjoy Baruah, V. Bonifaci, A. Marchetti-Spaccamela

引用次数: 82

Parallelism-Aware Memory Interference Delay Analysis for COTS Multicore Systems 基于并行感知的COTS多核系统内存干扰延迟分析

2015 27th Euromicro Conference on Real-Time Systems Pub Date : 2014-07-25 DOI: 10.1109/ECRTS.2015.24

H. Yun, R. Pellizzoni, P. K. Valsan

{"title":"Parallelism-Aware Memory Interference Delay Analysis for COTS Multicore Systems","authors":"H. Yun, R. Pellizzoni, P. K. Valsan","doi":"10.1109/ECRTS.2015.24","DOIUrl":"https://doi.org/10.1109/ECRTS.2015.24","url":null,"abstract":"In modern Commercial Off-The-Shelf (COTS) multicore systems, each core can generate many parallel memory requests at a time. The processing of these parallel requests in the DRAM controller greatly affects the memory interference delay experienced by running tasks on the platform. In this paper, we present a new parallelism-aware worst-case memory interference delay analysis for COTS multicore systems. The analysis considers a COTS processor that can generate multiple outstanding requests and a COTS DRAM controller that has a separate read and write request buffer, prioritizes reads over writes, and supports out-of-order request processing. Focusing on LLC and DRAM bank partitioned systems, our analysis computes worst-case upper bounds on memory-interference delays, caused by competing memory requests. We validate our analysis on a Gem5 full-system simulator modeling a realistic COTS multicore platform, with a set of carefully designed synthetic benchmarks as well as SPEC2006benchmarks. The evaluation results show that our analysis produces safe upper bounds in all tested benchmarks, while the current state-of-the-art analysis significantly under-estimates the delays.","PeriodicalId":243434,"journal":{"name":"2015 27th Euromicro Conference on Real-Time Systems","volume":"184 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114156236","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: 80