A Survey of Application Memory Usage on a National Supercomputer: An Analysis of Memory Requirements on ARCHER

Abstract

In this short paper we set out to provide a set of modern data on the actual memory per core and memory per node requirements of the most heavily used applications on a contemporary, national-scale supercomputer. This report is based on data from all jobs run on the UK national supercomputing service, ARCHER, a 118,000 core Cray XC30, in the 1 year period from 1 st July 2016 to 30 th June 2017 inclusive. Our analysis shows that 80% of all usage on ARCHER has a maximum memory use of 1 GiB/core or less (24 GiB/node or less) and that there is a trend to larger memory use as job size increases. Analysis of memory use by software application type reveals differences in memory use between periodic electronic structure, atomistic N-body, grid-based climate modelling, and grid-based CFD applications. We present an analysis of these differences, and suggest further analysis and work in this area. Finally, we discuss the implications of these results for the design of future HPC systems, in particular the applicability of high bandwidth memory type technologies.

A performance analysis of the first generation of HPC‐optimized Arm processors

“…Therefore, a fixed problem size per core was used for this study with a spatial grid of 1024 × 2 × 2 per MPI rank, 136 angles per octant, and 32 groups, with one MPI rank per physical core. The footprint of the angular flux solution in this case is just over 1 GB, which is roughly in line with typical ARCHER usage . The figure of merit for this application is the grind time , which is a normalized value taking into account differing problem sizes.…”

“…As such, it is important to ensure that the most heavily used codes are tested and evaluated. To that end, eight real applications have been selected for this study, taken from the top 10 most used codes on ARCHER, UK's national supercomputer . These applications represent over 50% of the usage of the whole supercomputer.…”

“…To that end, eight real applications have been selected for this study, taken from the top 10 most used codes on ARCHER, UK's national supercomputer. 1 These applications represent over 50% of the usage of the whole supercomputer. Therefore, the performance of these codes on any architecture captures the interests of a significant fraction of UK HPC users, and any change in the performance of these codes directly from the use of different architectures is important to quantify.…”

“…The top 10 most heavily used codes that are run on UK's national supercomputer, ARCHER (an Intel x86‐based Cray XC30 system), along with a selection of mini‐apps, proxy applications, and applications from project partners, provide good representation of the styles of codes used by today's HPC community . As such, they provide an ideal vehicle for which to benchmark the new Cavium ThunderX2 architecture, and the Isambard system presents a unique opportunity for such comparative benchmarking.…”

Benchmarking the first generation of production quality Arm‐based supercomputers

“…Some of our benchmarks come from the most heavily used codes that are run on the UK's national supercomputer, ARCHER (a Cray XC30 system), and to these, we add a set of well‐known mini‐apps. Together, this set provides representative coverage of the types of codes used by citizens of today's HPC community . Being a standard XC50 system, Isambard presents a unique opportunity for comparative benchmarking against XC50 machines based on mainstream x86 CPUs, including Broadwell and Skylake processors.…”