Scheduling the I/O of HPC Applications Under Congestion

Ana Gainaru (1) , Guillaume Aupy (2, 3, 4) , Anne Benoit (2, 3) , Franck Cappello (5, 6, 7) , Yves Robert (2, 3, 8) , Marc Snir (7, 1)

1 UIUC - Department of Computer Science [UIUC]
2 ROMA - Optimisation des ressources : modèles, algorithmes et ordonnancement
3 LIP - Laboratoire de l'Informatique du Parallélisme
4 Penn State - Pennsylvania State University
5 LRI - Laboratoire de Recherche en Informatique
6 JLPC - Joint Laboratory for Petascale Computing [Illinois]
7 ANL - Argonne National Laboratory [Lemont]
8 The University of Tennessee [Knoxville]

A significant percentage of the computing capacity of large-scale platforms is wasted because of interferences incurred by multiple applications that access a shared parallel file system concurrently. One solution to handling I/O bursts in large-scale HPC systems is to absorb them at an intermediate storage layer consisting of burst buffers. However, our analysis of the Argonne's Mira system shows that burst buffers cannot prevent congestion at all times. Consequently, I/O performance is dramatically degraded, showing in some cases a decrease in I/O throughput of 67%. In this paper, we analyze the effects of interference on application I/O bandwidth and propose several scheduling techniques to mitigate congestion. We show through extensive experiments that our global I/O scheduler is able to reduce the effects of congestion, even on systems where burst buffers are used, and can increase the overall system throughput up to 56%. We also show that it outperforms current Mira I/O schedulers.

Domaines: Calcul parallèle, distribué et partagé [cs.DC]

Ana Gainaru, Guillaume Aupy, Anne Benoit, Franck Cappello, Yves Robert, et al.. Scheduling the I/O of HPC Applications Under Congestion. IEEE International Parallel and Distributed Processing Symposium, IPDPS 2015, Hyderabad, India, May 25-29, 2015, May 2015, Hyderabad, India. ⟨10.1109/IPDPS.2015.116⟩. ⟨hal-01251938⟩