一种任务类型敏感的J2EE事务调度算法  

A Task-Type Aware Transaction Scheduling Algorithm in J2EE

作　　者：丁晓宁[1] 张昕[1] 金蓓弘[1] 黄涛[1] 

机构地区：[1]中国科学院软件研究所软件工程技术研究中心

出　　处：《软件学报》2006年第1期31-38,共8页Journal of Software

基　　金：国家高技术研究发展计划(863);国家重点基础研究发展规划(973)~~

摘　　要：J2EE(Java 2 platform enterprise edition)是构建分布式企业应用的基础中间件平台,当前的J2EE事务对资源的访问调度仍然是简单的先来先服务策略,导致服务器负载很重时,次要任务和关键任务争夺有限的资源,降低了关键任务的性能与成功率.为此,有必要识别任务类型,在资源不足时优先保证关键任务事务的执行.但提交给J2EE的事务基于交互方式执行,且缺乏必要的调度信息,因而不能简单地沿用已有的优先级驱动调度算法.提出一种新的事务调度算法TMPBP(threaded multi-queue priority-based protocol),该算法能够安全、有效地提高系统重负载情况下关键事务的服务质量,防止饥饿和优先级倒置.TMPBP包含了一种新的启发式优先级分派算法HRS(heuristic resource statistics),可以在调度信息缺乏的J2EE环境下动态识别关键事务.结果表明,通过合理地选择参数,TMPBP算法能够显著地提高关键事务的服务质量.J2EE is the primary middleware platform for distributed enterprise applications. Current J2EE （Java 2 platform enterprise edition） transaction scheduling to entity beans is still a simple First -Come First-Served （FCFS） policy. Due to this simple policy, transaction manager is unable to distinguish the key tasks from the trivial ones and the performance of the key tasks is reduced when the server＇s load is heavy. Since some characteristics of J2EE middleware, the traditional scheduling algorithms can not be applied to J2EE directly. This paper puts forward a scheduling algorithm named TMPBP （threaded multi-queue priority-based protocol）. The algorithm includes a heuristic priority assignment algorithm named HRS, which can recognize the key tasks dynamically. TMPBP improves the Quality of Service （QoS） of the key tasks effectively under heavy load. It is safe and has no starvation or priority inversion. The performance experiments indicate that a consider able improvement on QoS of key tasks has been achieved under the proper parameters of the algorithm.

关 键 词：J2EE 事务调度 优先级 启发式 

分 类 号：TP311[自动化与计算机技术—计算机软件与理论]