@inproceedings {Simula.netsys.16,
	title = {Achieving Predictable High Performance in Imbalanced Fat Trees},
	journal = {Proceedings of the 16th IEEE International Conference on Parallel and Distributed Systems},
	year = {2010},
	month = {December},
	pages = {381-388},
	publisher = {IEEE Computer Society},
	type = {Conference},
	abstract = {Abstract-The fat-tree topology has become a popular choice for InfiniBand fabrics due to its inherent deadlock freedom, fault-tolerance and full bisection bandwidth. InfiniBand is used by more than 40\% of the systems on the latest Top 500 list, and many of these systems are based on a fat-tree topology. However, the current InfiniBand fat-tree routing algorithm suffers from flaws that reduce its scalability and flexibility. Counter-intuitively, the achievable throughput per node deteriorates both when the number of nodes in a tree decreases or when the node distribution among leaves is nonuniform. In this paper, we identify the weaknesses of the current enhanced fat-tree routing algorithm in OpenFabrics Enterprise Distribution and we propose extensions to it that alleviate all performance problems related to node distribution. The new algorithm is implemented in OpenSM for real world evaluation and for future contribution to the OpenFabrics community. We demonstrate that our solution allows to achieve a predictable high throughput regardless of the number of nodes and their distribution. Furthermore, the simulations show that our extensions improve throughput up to 30\% depending on topology size and node distribution.},
	isbn = {978-0-7695-4307-9},
	author = {Bogdanski, Bartosz and Frank Olaf {Sem-Jacobsen} and Reinemo, Sven-Arne and Skeie, Tor and Holen, Line and Lars Paul {Huse}},
	editor = {Huang, Xiaoxia}
}
@inproceedings {Simula.nd.417,
	title = {First Experiences With Congestion Control in InfiniBand Hardware},
	journal = {2010 IEEE International Symposium on Parallel \& Distributed Processing (IPDPS)},
	year = {2010},
	pages = {1-12},
	publisher = {IEEE},
	type = {Conference},
	abstract = {In lossless interconnection networks congestion control (CC) can be an effective mechanism to achieve high performance and good utilization of network resources. Without CC, congestion on one link may grow into a congestion tree that can degrade the performance severely. This degradation can affect not only contributors to the congestion, but also throttles innocent traffic flows in the network. The InfiniBand standard describes CC functionality for detecting and resolving congestion. The InfiniBand CC concept is rich in the way that it specifies a set of parameters that can be tuned in order to achieve effective CC. There is, however, limited experience with the InfiniBand CC mechanism. To the best of our knowledge, only a few simulation studies exist. Recently, InfiniBand CC has been implemented in hardware, and in this paper we present the first experiences with such equipment. We show that the implemented InfiniBand CC mechanism effectively resolves congestion and improves fairness by solving the parking lot problem, if the CC parameters are appropriately set. By conducting extensive testing on a selection of the CC parameters, we have explored the parameter space and found a subset of parameter values that leads to efficient CC for our test scenarios. Furthermore, we show that the InfiniBand CC increases the performance of the well known HPC Challenge benchmark in a congested network.},
	isbn = {978-1-4244-6442-5},
	doi = {10.1109/IPDPS.2010.5470419},
	author = {Ernst Gunnar {Gran} and Eimot, Magne and Reinemo, Sven-Arne and Skeie, Tor and Lysne, Olav and Lars Paul {Huse} and Shainer, Gilad},
	editor = {Phillips, Cynthia}
}
@misc {Simula.netsys.10,
	title = {First Experiences With Congestion Control in InfiniBand Hardware},
	howpublished = {Invited talk at the HPC Advisory Council Switzerland Workshop 2010},
	year = {2010},
	month = {March},
	abstract = {In InfiniBand networks congestion control (CC) can be an effective mechanism to achieve high performance and high utilisation of network resources. Without CC, congestion in one node may severely degrade overall performance. In this talk we introduce the problem of congestion and how it can be avoided with InfiniBand congestion control.},
	author = {Reinemo, Sven-Arne and Ernst Gunnar {Gran} and Eimot, Magne and Skeie, Tor and Lysne, Olav and Lars Paul {Huse} and Shainer, Gilad}
}
@article {Simula.ND.18,
	title = {The Interconnection Network - Architectural Challenges for Utility Computing Data Centres},
	journal = {IEEE Computer Magazine},
	volume = {41},
	number = {9},
	year = {2008},
	month = {September},
	pages = {62-69},
	publisher = {IEEE},
	abstract = {The mode of operation employed by Computational Data Centres that offer Utility Computing differs significantly from that of traditional supercomputers and server clusters and as such present new architectural problems that should be studied and solved. In this paper we concentrate on issues facing the interconnection network. We argue that this is a part of the overall architecture where shortcomings in present day solutions are most severe and present a model for the mode of operation of a Utility Computing Data Centre where virtualisation is a main ingredient. Based on this model we identify several areas where the interconnection network faces new challenges and needs new solutions. In each of these areas we give a brief introduction to previous results before we identify the new challenges.},
	author = {Lysne, Olav and Reinemo, Sven-Arne and Skeie, Tor and {\r A}shild Gr{\o}nstad {Solheim} and S{\o}dring, Thomas and Lars Paul {Huse} and Bj{\o}rn Dag {Johnsen}}
}
@techreport {25342,
	title = {The Interconnection Network - Architectural Challenges for Utility Computing Data Centres},
	year = {2007},
	note = {This technical report is an earlier version of a published journal article. The published version can be found here:https://www.simula.no/publications/interconnection-network-architectural-challenges-utility-computing-data-centres},
	publisher = {Simula Research Laboratory},
	author = {Lysne, Olav and Reinemo, Sven-Arne and Skeie, Tor and {\r A}shild Gr{\o}nstad {Solheim} and S{\o}dring, Thomas and Lars Paul {Huse} and Bj{\o}rn Dag {Johnsen}}
}
@inproceedings {ND.6.Gjessing.1999,
	title = {Running the SAR Application on a Cluster of PCs Connected With SCI Using a HIC Based SCI Switch},
	journal = {Conference Proceedings of SCI Europe{\textquoteright}99 in Euro-Par 99},
	year = {1999},
	note = {ISBN 82-14-00014-9},
	type = {1},
	address = {Toulouse},
	author = {Gjessing, Stein and Maus, Arne and Str{\o}m, I. and Lars Paul {Huse}}
}
