基于服务质量需求的存储系统动态优先权调度策略

多媒体应用要求存储系统提供保证服务质量的数据访问服务，响应时间超过延迟上限的访问请求必须小于一定的比例．基于服务质量需求的动态优先权调度策略（QADPS）根据多媒体应用接受存储系统服务的历史信息，计算多媒体应用的服务质量失败距离；并为失败距离较小的多媒体应用分配较高的调度优先权．QADPS根据多媒体应用的不同服务质量需求，实现了有差别的调度：多媒体应用的服务质量需求越严格，它的访问请求被调度的机会越高．QADPS能够在保证服务质量的前提下，支持更多的并发多媒体应用．

Quality of Service Aware Dynamic Priority Scheduling Scheme for the Mixed Class Multimedia Workloads in the Storage Systems

QADPS(QoS-aware dynamic priority scheduling scheme),a new scheduling scheme for meeting the different QoS requirements of multimedia applications is introduced in this paper.When retrieving data from the storage systems,multimedia applications need the guarantee of QoS.The fraction of requests whose response time exceeds a specific delay limit must be below a certain proportion.Different multimedia applications may have different QoS requirements in the mixed multimedia workloads.Based on the history of a multimedia application receiving service,its QoS failed-distance can be calculated.The basic idea of QADPS is to assign higher priority to the multimedia applications that have shorter failed-distance.Using this scheme,the requests of the multimedia applications with stricter QoS requirements can achieve more chances of service applied by the storage systems.The effectiveness of this approach is evaluated through simulation.Compared with the conventional scheme,QADPS substantially increases the number of the concurrent multimedia applications.