QoS约束的云工作流调度算法

将云计算和工作流两者结合起来，并根据用户关心的QoS中执行时间和执行费用问题，针对工作流调度策略在云环境下调度实例密集型工作流时效率不高的问题优化资源调度策略，给出云工作流调度模型，提出一种基于QoS约束的云工作流调度算法MSCWQ(modifiedschedulingalgorithmforcloudworkflowbasedonQoS).该算法利用DAG(directedacyclicgraph)进行建模，优化资源策略，保证在最晚结束时间内使整个工作流实例的执行费用尽可能小.实验结果表明，在调度实例密集型云工作流时，该算法能有效提升科学工作流的执行效率，并能减少资源的使用费用.

Modified Scheduling Algorithm for Cloud Workflow Based on QoS

According to the users’ requirements of QoS time and execution costs， the scheduling strategies for workflow were modified by combining the cloud computing and workflow. For the problem that workflow efficiency of instance intensive cloud workflows was not high in a cloud environment， the cloud workflow scheduling model and the modified scheduling algorithm for cloud workflow were proposed based on QoS. DAG was used in the algorithm， and resource strategy was modified to meet the latest execution time under the premise of minimizing the entire workflow execution costs. The experimental results showed that the efficiency effectively improved and the cost of using resource was reduced with the proposed algorithm.