检索结果-内蒙古大学图书馆

priority inheritance IN SOFT REAL-TIME DATABASES

REAL-TIME SYSTEMS 1992年第3期4卷 243-268页

作者： HUANG, JD STANKOVIC, JA RAMAMRITHAM, K TOWSLEY, D PURIMETLA, B UNIV MASSACHUSETTS DEPT DEV THERAPEUTAMHERSTMA 01003

Due to resource sharing among tasks, priority inversion can occur during priority-driven preemptive scheduling. In this work, we investigate solutions to the priority inversion problem in a soft real-time database environment where two-phase locking is employed for concurrency control. We examine two basic schemes for addressing the priority inversion problem, one based on priority inheritance and the other based on priority abort. We also study a new scheme, called conditional priority inheritance, which attempts to capitalize on the advantages of each of the two basic schemes. In contrast with previous results obtained in real-time operating systems, our performance studies, conducted on an actual real-time database testbed, indicate that the basic priority inheritance protocol is inappropriate for solving the priority inversion problem in real-time database systems. We identify the reasons for this performance. We also show that the conditional priority inheritance scheme and the priority abort scheme perform well for a wide range of system workloads.

关键词： REAL-TIME DATABASE SYSTEMS CONCURRENCY CONTROL SCHEDULING priority inheritance priority INVERSION IMPLEMENTATION PERFORMANCE EVALUATION

来源：评论

学校读者我要写书评

暂无评论

priority inheritance protocol in Ada 95

引用

INFORMATION AND SOFTWARE TECHNOLOGY 1996年第2期38卷 121-125页

作者： AbuRas, J University of Houston—Clear Lake POB 52383 Houston Texas 77052 USA

priority inversion is any situation where low priority tasks are served before higher priority tasks. It is recognized as a serious problem for real-time systems. In this paper, we describe the fundamental mechanisms in Ada 95 to reduce uncontrolled priority inversion in realtime scheduling. We implemented the priority inheritance protocol (PIP) in Ada 95 to better illustrate Ada's new usefulness for real-time programming. A detailed discussion of this protocol and other related issues are presented.

关键词： priority inversion priority inheritance real-time systems

来源：评论

学校读者我要写书评

暂无评论

A priority inheritance Centered Locking Protocol for DRTDBS

引用

WIRELESS PERSONAL COMMUNICATIONS 2023年第2期130卷 987-1004页

作者： Pandey, Sarvesh Shanker, Udai Banaras Hindu Univ Comp Sci MMV Varanasi India MMM Univ Technol Dept Comp Sci & Engn Gorakhpur 273010 India

In distributed real-time applications, the static 2 Phase Locking with High priority (S2PL-HP) protocol may resolve data conflict(s) among transactions executing concurrently. S2PL-HP is virtuously free from the priority inversion that may arise due to executing-executing conflict-both the transactions in the execution phase. However, its performance may degrade because of other problems, i.e., cyclic restart and unnecessary abort, starvation of transactions of longer length, and system resource wastage. We propose a new priority inheritance (PRIN) centered locking protocol to resolve the above problems. PRIN checks the wastage of system resources by preventing cyclic restart and unnecessary abort using the priority inheritance approach. It is also free from deadlock and reduces the effects of lengthy transaction starvation. The system performance is measured using the transaction miss percentage metric. We developed the simulator to assess the performance of the proposed protocol;the results confirm that our system, PRIN, achieves 1.05 x-1.23 x performance improvement over the state-of-the-art systems.

关键词： Transaction Two phase locking DRTDBS S2PL-HP priority inheritance

来源：评论

学校读者我要写书评

暂无评论

Verifying Nested Lock priority inheritance in RTEMS with Java Pathfinder 18th

Verifying Nested Lock Priority Inheritance in RTEMS with Jav...

引用

18th International Conference on Formal Engineering Methods (ICFEM)

作者： Gadia, Saurabh Artho, Cyrille Bloom, Gedare Univ Southern Calif Los Angeles CA USA Natl Inst Adv Ind Sci & Technol Osaka Japan KTH Royal Inst Technol Stockholm Sweden Howard Univ Washington DC 20059 USA

ISBN: (纸本)9783319478463;9783319478456

Scheduling and synchronization algorithms for uniprocessor real-time systems benefit from the rich theory of schedulability analysis, and yet translating these algorithms to practical implementations can be challenging. This paper presents a Java model of the priority inheritance protocol for mutual exclusion, as implemented in the RTEMS open-source real-time operating system. We verified this model using Java Pathfinder to detect potential data races, deadlocks, and priority inversions. JPF detected a known bug in the RTEMS implementation, which we modified along with the Java model. Verification of the modified model showed the absence of data races, deadlocks, and established nine protocol-specific correctness properties.

关键词： Java Pathfinder RTEMS priority inheritance

来源：评论

学校读者我要写书评

暂无评论

RT-Linux priority reversal and priority inheritance mechanisms

RT-Linux priority reversal and priority inheritance mechanis...

引用

5th International Conference on Measuring Technology and Mechatronics Automation (ICMTMA)

作者： Zhu, Jianlin Liu, Keyou Tu, Yu Yuan, Yi Gao, Xiaoliang Hunan Sci & Technol Econ Vocat Coll Elect & Informat Engn Inst Hengyang 421009 Peoples R China Xiangtan Univ Sch Mech Engn Xiangtan 411105 Peoples R China

ISBN: (纸本)9780769549323;9781467356527

RT-Linux is a kind of embedded Linux, its real time performance is relative high among numerous kind of embedded Linux, but it requires the operation system have high real time performance and using priority inheritance protocol to solve the priority reverse problem in RT-Linux. In order to trace the system roundly, a kernel trace tool is designed, and used this tool to test the improvement. The test results show that the work eliminated the priority reverse problem, and advanced the real time performance of RT-Linux.

关键词： RT-Linux kernel trace tool priority inheritance priority reverse

来源：评论

学校读者我要写书评

暂无评论

A One Phase priority inheritance Commit Protocol 14th

A One Phase Priority Inheritance Commit Protocol

引用

14th International Conference on Distributed Computing and Internet Technology (ICDCIT)

作者： Pandey, Sarvesh Shanker, Udai Madan Mohan Malaviya Univ Technol Comp Sci & Engn Dept Gorakhpur Uttar Pradesh India

ISBN: (纸本)9783319723440;9783319723433

High priority two phase locking (HP2PL) concurrency control algorithm can be used for accessing of data items to resolve conflicts amongst the concurrently executing transactions. Inclusion of priority inversion and data inaccessibility are the most undesirable problems in transactions' execution which seriously affect the system performance. Previously developed protocols for resolving such issues put a lot of messages and time overhead which is not desirable. In distributed real-time database system (DRTDBS), basic aim is to minimize the number of transactions missing their deadline. This can be achieved by minimizing commit time. In this paper, A One Phase priority inheritance Commit Protocol (OPPIC) has been proposed specifically reducing one round of message transfer among coordinator and participating cohorts' sites in case of priority inversion problem at any of the cohort of low priority transaction. Focus of this protocol is to minimize the priority inversion duration that in turn minimizes commit time. A distributed database system is simulated for measuring the performance of this protocol with 2PC and PIC protocols. The results confirm the significant improvement in system performance with the OPPIC protocol.

关键词： Concurrency control Commit protocol priority inheritance priority inversion Distributed real-time database systems

来源：评论

学校读者我要写书评

暂无评论

Deadlock-Free Method for Multi-Agent Pickup and Delivery Problem Using priority inheritance with Temporary priority

引用

Procedia Computer Science 2022年 207卷 1552-1561页

作者： Yukita Fujitani Tomoki Yamauchi Yuki Miyashita Toshiharu Sugawara Department of Computer Science and Communications Engineering Waseda University Tokyo 1698555 Japan

This paper proposes a control method for the multi-agent pickup and delivery problem (MAPD problem) by extending the priority inheritance with backtracking (PIBT) method to make it applicable to more general environments. PIBT is an effective algorithm that introduces a priority to each agent, and at each timestep, the agents, in descending order of priority, decide their next neighboring locations in the next timestep through communications only with the local agents. Unfortunately, PIBT is only applicable to environments that are modeled as a bi-connected area, and if it contains dead-ends, such as tree-shaped paths, PIBT may cause deadlocks. However, in the real-world environment, there are many dead-end paths to locations such as the shelves where materials are stored as well as loading/unloading locations to transportation trucks. Our proposed method enables MAPD tasks to be performed in environments with some tree-shaped paths without deadlock while preserving the PIBT feature; it does this by allowing the agents to have temporary priorities and restricting agents’ movements in the trees. First, we demonstrate that agents can always reach their delivery location without deadlock. Our experiments indicate that the proposed method is very efficient, even in environments where PIBT is not applicable, by comparing them with those obtained using the well-known token passing method as a baseline.

关键词： Multi-agent systems Pickup delivery problem priority inheritance

来源：评论

学校读者我要写书评

暂无评论

A VLSI priority PACKET QUEUE WITH inheritance AND OVERWRITE

引用

IEEE TRANSACTIONS ON VERY LARGE SCALE INTEGRATION (VLSI) SYSTEMS 1995年第2期3卷 245-253页

作者： PICKER, D FELLMAN, RD Dept. of Electr. & Comput. Eng. California Univ. San Diego La Jolla CA USA

Reliable priority-based flow-control is essential for real-time applications involving hard-deadlines. However, the use of first-in-first-out (FIFO) queues in such systems introduces priority inversion resulting in unbounded transmission delays. For this reason, a priority transmission queue is critical for multimedia and mission-critical systems. Yet very few priority queue implementations exist. This paper presents the design of a novel VLSI priority packet queue (PPQ), implemented in 1,2 mu m CMOS technology. It achieves fast operation by manipulating its contents in terms of packet segments, rather than individual words. Similar to paged memory, this new segmented architecture greatly reduces implementation cost by reusing segments and avoiding storage area fragmentation. By distributing the computationally intensive priority comparison operation over the access time for an entire segment, the PPQ achieves 96% of the speed of a high-speed packet FIFO. The PPQ can either perform priority inheritance or overwrite lower priority packets to minimize the impact of queue overflow. In addition, it is suitable as a general computer network interface buffer, since it robustly handles asynchronous read and write clocks of greatly disparate frequencies. Our initial implementation achieves well over twice the speed of a nonpipelined approach with minimal additional overhead. Furthermore, scaling this design to larger capacities and more priority levels results in an even greater improvement in speed over conventional approaches.

关键词： PACKET COMMUNICATION NETWORK priority inheritance priority QUEUE RATE MONOTONIC SCHEDULING REAL-TIME SYSTEMS VLSI

来源：评论

学校读者我要写书评

暂无评论

The PROMPT real-time commit protocol

引用

IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS 2000年第2期11卷 160-181页

作者： Haritsa, JR Ramamritham, K Gupta, R Indian Inst Sci Supercomp Educ & Res Ctr Database Syst Lab Bangalore 560012 Karnataka India Univ Massachusetts Dept Comp Sci Amherst MA 01003 USA Indian Inst Technol Bombay 400076 Maharashtra India Goldencom Technol Fremont CA 94539 USA

We investigate the performance implications of providing transaction atomicity for firm-deadline real-time applications operating on distributed data. Using a detailed simulation model, the real-time performance of a representative set of classical transaction commit protocols is evaluated. The experimental results show that data distribution has a significant influence on real-time performance and that the choice of commit protocol clearly affects the magnitude of this influence. We also propose and evaluate a new commit protocol, PROMPT (Permits Reading Of Modified Prepared-data for Timeliness), that is specifically designed for the realtime domain. PROMPT allows transactions to "optimistically" borrow, in a controlled manner, the updated data of transactions currently in their commit phase. This controlled borrowing reduces the data inaccessibility and the priority inversion that is inherent in distributed real-time commit processing. A simulation-based evaluation shows PROMPT to be highly successful, as compared to the classical commit protocols, in minimizing the number of missed transaction deadlines. in fact, its performance is close to the best on-line performance that could be achieved using the optimistic lending approach. Further, it is easy to implement and incorporate in current database system software. Finally, PROMPT is compared against an alternative priority inheritance-based approach to addressing priority inversion during commit processing. The results indicate that priority inheritance does not provide tangible performance benefits.

关键词： distributed real-time database commit protocol two phase commit three phase commit priority inheritance performance evaluation

来源：评论

学校读者我要写书评

暂无评论

Kernel thread scheduling in real-time Linux for wearable computers

引用

ETRI JOURNAL 2007年第3期29卷 270-280页

作者： Kang, Dongwook Lee, Woojoong Park, Chanik POSTECH Dept Comp Sci & Engn Pohang South Korea

In Linux, real-time tasks are supported by separating real-time task priorities from non-real-time task priorities. However, this separation of priority ranges may not be effective when real-time tasks make the system calls that are taken care of by the kernel threads. Thus, Linux is considered a soft real-time system. Moreover, kernel threads are configured to have static priorities for throughputs. The static assignment of priorities to kernel threads causes trouble for real-time tasks when real-time tasks require kernel threads to be invoked to handle the system calls because kernel threads do not discriminate between real-time and non-real-time tasks. We present a dynamic kernel thread scheduling mechanism with weighted average priority inheritance protocol (PIP), a variation of the PIP. The scheduling algorithm assigns proper priorities to kernel threads at runtime by monitoring the activities of user-level real-time tasks. Experimental results show that the algorithms can greatly improve the unexpected execution latency of real-time tasks.

关键词： real-time scheduling Linux kernel threads priority inheritance wearable computers

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：