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Publications of SPCL
|D. De Sensi, S. Di Girolamo, T. Hoefler:|
|Mitigating Network Noise on Dragonfly Networks through Application-Aware Routing|
(In Proceedings of the International Conference for High Performance Computing, Networking, Storage and Analysis (SC19), Nov. 2019, )
AbstractSystem noise can negatively impact the performance of HPC systems, and interconnection network is one of the main factors contributing to this problem. To mitigate this effect, adaptive routing sends packets on non-minimal paths if they are less congested. However, while this may mitigate interference caused by congestion, it also generates more traffic since packets traverse additional hops, causing in turn congestion on other applications and on the application itself. In this paper, we first describe how to estimate network noise. By following these guidelines, we show how noise can be reduced by using routing algorithms which select minimal paths with a higher probability. We exploit this knowledge to design an algorithm which changes the probability of selecting minimal paths according to the characteristics of the application. We validate our solution on microbenchmarks and applications on two systems relying on a Dragonfly interconnection network, showing a reduction of network noise.
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