Abstract
The move towards high-performance computing (HPC) ap-
plications comprised of coupled codes and the need to dra-
matically reduce data movement is leading to a reexami-
nation of time-sharing vs. space-sharing in HPC systems.
In this paper, we discuss and begin to quantify the perfor-
mance impact of a move away from strict space-sharing of
nodes for HPC applications. Specifically, we examine the po-
tential performance cost of time-sharing nodes between ap-
plication components, we determine whether a simple coor-
dinated scheduling mechanism can address these problems,
and we research how suitable simple constraint-based opti-
mization techniques are for solving scheduling challenges in
this regime. Our results demonstrate that current general-
purpose HPC system software scheduling and resource al-
location systems are subject to significant performance de-
ciencies which we quantify for six representative applica-
tions. Based on these results, we discuss areas in which ad-
ditional research is needed to meet the scheduling challenges
of next-generation HPC systems.
