Predicting resource usage for enhanced job scheduling for opportunistic resources in HEP

To overcome the computing challenge in High Energy Physics available resources must be utilized as efficiently as possible. This targets algorithmic challenges in the workflows itself but also the scheduling of jobs to compute resources. To enable the best possible scheduling, job schedulers require accurate information about resource consumption of a job before it is even executed. It is the responsibility of the user to provide an accurate resource estimate required for jobs. However, this is quite a challenge for users as they (i) want to ensure their jobs to run correctly, (ii) must manage to deal with heterogeneous compute resources and (iii) face intransparent library dependencies and frequent updates. Users therefore tend to specify resource requests with an ample buffer. This inaccuracy results in inefficient utilisation by either blocking unused resources or exceeding reserved resources. Especially in the context of opportunistic resource provisioning the inaccuracies have an even broader impact that does not even target utilisation of resources but also composition of the most suitable resources. The contribution of this paper is an analysis of production and end-user workflows in HEP with regards to optimizing the various resources types. We further propose a method to improve user estimates.