The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform

Gyehyeon Gyeong - One of the best experts on this subject based on the ideXlab platform.

Kwangsun Ko - One of the best experts on this subject based on the ideXlab platform.

Seonggoo Kang - One of the best experts on this subject based on the ideXlab platform.

Jialu Liu - One of the best experts on this subject based on the ideXlab platform.

  • maintaining temporal consistency pessimistic vs optimistic concurrency control
    IEEE Transactions on Knowledge and Data Engineering, 1995
    Co-Authors: Xiaohui Song, Jialu Liu
    Abstract:

    We study the performance of concurrency control algorithms in maintaining temporal consistency of shared data in hard real time systems. In our model, a hard real time system consists of periodic tasks which are either write only, read only or update transactions. Transactions may share data. Data objects are temporally inconsistent when their ages and dispersions are greater than the absolute and relative thresholds allowed by the application. Real time transactions must read temporally consistent data in order to deliver correct results. Based on this model, we have evaluated the performance of two well known classes of concurrency control algorithms that handle multiversion data: the two phase locking and the optimistic algorithms, as well as the rate monotonic and earliest deadline first scheduling algorithms. The effects of using the Priority Inheritance and stack based protocols with lock based concurrency control are also studied. >

K. Sakamura - One of the best experts on this subject based on the ideXlab platform.

  • Priority Inheritance spin locks for multiprocessor real time systems
    International Symposium on Parallel Architectures Algorithms and Networks, 1996
    Co-Authors: Caidong Wang, Hiroaki Takada, K. Sakamura
    Abstract:

    When a real-time system is realized on a shared-memory multiprocessor Priority-ordered spin locks are often required to reduce Priority inversions. However, simple Priority-ordered spin locks can cause uncontrolled Priority inversions when they are used for nested spin locks. This paper points out the problem of uncontrolled Priority inversions in the context of spin locks and proposes Priority Inheritance spin locks, spin lock algorithms that are enhanced with the Priority Inheritance scheme, to solve the problem. Two algorithms of Priority Inheritance spin locks are presented and their effectiveness is demonstrated through performance measurements.

  • Experimental implementations of Priority Inheritance semaphore on ITRON-specification kernel
    Proceedings of the 11th TRON project International Symposium, 1994
    Co-Authors: H. Takada, K. Sakamura
    Abstract:

    Using Priority Inheritance protocols is an effective approach to solve the problem of uncontrolled Priority inversion, which is among the major sources of deadline violations in hard real-time systems. In this paper, some approaches to incorporate Priority Inheritance to the ITRON specification are discussed. As the result, we propose two specifications of Priority Inheritance semaphore functions with which the basic Priority Inheritance protocol can be realized, and implement both of them for evaluation. The run-time performance and memory requirements of the functions are evaluated with the implementations.