233 research outputs found
Information Spreading on Almost Torus Networks
Epidemic modeling has been extensively used in the last years in the field of
telecommunications and computer networks. We consider the popular
Susceptible-Infected-Susceptible spreading model as the metric for information
spreading. In this work, we analyze information spreading on a particular class
of networks denoted almost torus networks and over the lattice which can be
considered as the limit when the torus length goes to infinity. Almost torus
networks consist on the torus network topology where some nodes or edges have
been removed. We find explicit expressions for the characteristic polynomial of
these graphs and tight lower bounds for its computation. These expressions
allow us to estimate their spectral radius and thus how the information spreads
on these networks
An In-Depth Analysis of the Slingshot Interconnect
The interconnect is one of the most critical components in large scale
computing systems, and its impact on the performance of applications is going
to increase with the system size. In this paper, we will describe Slingshot, an
interconnection network for large scale computing systems. Slingshot is based
on high-radix switches, which allow building exascale and hyperscale
datacenters networks with at most three switch-to-switch hops. Moreover,
Slingshot provides efficient adaptive routing and congestion control
algorithms, and highly tunable traffic classes. Slingshot uses an optimized
Ethernet protocol, which allows it to be interoperable with standard Ethernet
devices while providing high performance to HPC applications. We analyze the
extent to which Slingshot provides these features, evaluating it on
microbenchmarks and on several applications from the datacenter and AI worlds,
as well as on HPC applications. We find that applications running on Slingshot
are less affected by congestion compared to previous generation networks.Comment: To be published in Proceedings of The International Conference for
High Performance Computing Networking, Storage, and Analysis (SC '20) (2020
OutFlank Routing: Increasing Throughput in Toroidal Interconnection Networks
We present a new, deadlock-free, routing scheme for toroidal interconnection
networks, called OutFlank Routing (OFR). OFR is an adaptive strategy which
exploits non-minimal links, both in the source and in the destination nodes.
When minimal links are congested, OFR deroutes packets to carefully chosen
intermediate destinations, in order to obtain travel paths which are only an
additive constant longer than the shortest ones. Since routing performance is
very sensitive to changes in the traffic model or in the router parameters, an
accurate discrete-event simulator of the toroidal network has been developed to
empirically validate OFR, by comparing it against other relevant routing
strategies, over a range of typical real-world traffic patterns. On the
16x16x16 (4096 nodes) simulated network OFR exhibits improvements of the
maximum sustained throughput between 14% and 114%, with respect to Adaptive
Bubble Routing.Comment: 9 pages, 5 figures, to be presented at ICPADS 201
Segment Switching: A New Switching Strategy for Optical HPC Networks
[EN] Photonics are becoming realistic technologies for implementing interconnection networks in near future Exascale supercomputer systems. Photonics present key features to design high-performance and scalable supercomputer networks, such as higher bandwidth and lower latencies than their electronic supercomputer networks counterparts. Some research work is focused on conventional network topologies built with photonic technologies, with the aim of taking advantage of photonic characteristics. Nevertheless, these approaches fail in that they keep low the network utilization. We looked into this downside and we found that circuit switching was the main performance limitation. In this article we propose a new switching mechanism, called Segment Switching, to address this constraint and improve the network utilization.
Segment Switching splits the circuit in segments of the whole path, and uses buffering on selected nodes on the network. Experimental results show that the devised approach signicantly outperforms photonic circuit switching in conventional torus and fat tree networks by 70% and 90%, respectively.This work was supported in part by the Ministerio de Ciencia, Innovacion y Universidades and in part by the European ERDF under Grant RTI2018-098156-B-C51.Duro, J.; Petit MartĂ, SV.; GĂłmez Requena, ME.; Sahuquillo Borrás, J. (2021). Segment Switching: A New Switching Strategy for Optical HPC Networks. IEEE Access. 9:43095-43106. https://doi.org/10.1109/ACCESS.2021.3058135S4309543106
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