  HPC users aim to improve their execution times without particular regard for
increasing system utilization. On the contrary, HPC operators favor increasing
the number of executed applications per time unit and increasing system
utilization. This difference in the preferences promotes the following
operational model. Applications execute on exclusively-allocated computing
resources for a specific time and applications are assumed to utilize the
allocated resources efficiently. In many cases, this operational model is
inefficient, i.e., applications may not fully utilize their allocated
resources. This inefficiency results in increasing application execution time
and decreasing system utilization. In this work, we propose a resourceful
coordination approach (RCA) that enables the cooperation between, currently
independent, batch- and application-level schedulers. RCA enables application
schedulers to share their allocated but idle computing resources with other
applications through the batch system. The effective system performance (ESP)
benchmark is used to assess the proposed approach. The results show that RCA
increased system utilization up to 12.6% and decreased system makespan by the
same percent without affecting applications' performance.
