Deadline-constrained workflow scheduling in software as a service Cloud

The advent of cloud computing as a new model of service provisioning in distributed systems,encourages researchers to investigate its benefits and drawbacks in executing scientific applications suchas workflows. in this model, the users request for available services according to their desired quality ofservice, and they are charged on a pay-per-use basis. one of the most challenging problems in clouds isworkflow scheduling, i.e., the problem of satisfying the qos of the user as well as minimizing the cost ofworkflow execution. in this paper, we propose a new qos-based workflow scheduling algorithm based ona novel concept called partial critical paths (pcp), which tries to minimize the cost of workflow executionwhile meeting a user-defined deadline. this algorithm recursively schedules the partial critical pathsending at previously scheduled tasks. the simulation results show that the performance of our algorithmis very promising.