Performance Analysis of Irregular Collective Communication with the Crystal Router Algorithm
2015 (English)In: Solving software challenges for exascale, 2015, 130-140 p.Conference paper (Refereed)
In order to achieve exascale performance it is important to detect potential bottlenecks and identify strategies to overcome them. For this, both applications and system software must be analysed and potentially improved. The EU FP7 project Collaborative Research into Exascale Systemware, Tools & Applications (CRESTA) chose the approach to co-design advanced simulation applications and system software as well as development tools. In this paper, we present the results of a co-design activity focused on the simulation code NEK5000 that aims at performance improvements of collective communication operations. We have analysed the algorithms that form the core of NEK5000's communication module in order to assess its viability on recent computer architectures before starting to improve its performance. Our results show that the crystal router algorithm performs well in sparse, irregular collective operations for medium and large processor number but improvements for even larger system sizes of the future will be needed. We sketch the needed improvements, which will make the communication algorithms also beneficial for other applications that need to implement latency-dominated communication schemes with short messages. The latency-optimised communication operations will also become used in a runtime-system providing dynamic load balancing, under development within CRESTA.
Place, publisher, year, edition, pages
2015. 130-140 p.
, Lecture Notes in Computer Science, ISSN 0302-9743 ; 8759
Collective operations, MPI, Performance tuning
IdentifiersURN: urn:nbn:se:kth:diva-170717DOI: 10.1007/978-3-319-15976-8_10ISI: 000355749700010ScopusID: 2-s2.0-84928920465ISBN: 978-3-319-15975-1ISBN: 978-3-319-15976-8OAI: oai:DiVA.org:kth-170717DiVA: diva2:839900
2nd International Conference on Exascale Applications and Software (EASC), APR 02-03, 2014, Stockholm, SWEDEN
QC 201507062015-07-062015-07-032015-07-06Bibliographically approved