Zusammenfassung
Application composition model promises to enable full utilization of extreme scale high performance computing (HPC) systems (aka ExaScale), wherein each composite application consists of several communicative components each of which is tightly coupled with a possibly especial software stack of its own. Heterogeneity of software stacks has encouraged the use of system virtualization technology to isolate executions of components on common shared resources. On the other hand, some components of composite applications, called loosely-coupled components, consist of a set of loosely-coupled CPU-intensive jobs. A given loosely-coupled component runs on a set of virtual machines (VMs), which in turn are distributed on some physical machines. A job scheduler has to assign/reassign jobs to VMs to adaptively cater for the resource provisioning and freeing of newly arrived jobs, and terminated jobs, respectively. Since VMs of several components may share common resources of a certain physical machine, and given that the job scheduler of each component is totally unaware of virtualization, the job scheduler of a loosely-coupled component does not know the status of physical machines. So, reconfiguration of the job scheduler’s parameters at runtime can give the true state of the physical machine based on which, the job scheduler can assign/reassign jobs to more suitable VMs. This paper presents a combination of ASSIGN-ROUTE online job scheduling and a reconfiguration technique allowing a given loosely-coupled component to balance its resource usage load, and thus improve the scaled execution of its loosely-coupled jobs. We prove that this technique reaches the load imbalance which is near to the optimal load imbalance for online deterministic unrelated parallel machine makespan minimization scheduling. We also show that the results of our experiments, support the theoretical achievements.
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