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Main Authors: Tarraf, Ahmad, Bandet, Alexis, Boito, Francieli, Pallez, Guillaume, Wolf, Felix
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2306.08601
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author Tarraf, Ahmad
Bandet, Alexis
Boito, Francieli
Pallez, Guillaume
Wolf, Felix
author_facet Tarraf, Ahmad
Bandet, Alexis
Boito, Francieli
Pallez, Guillaume
Wolf, Felix
contents Many HPC applications perform their I/O in bursts that follow a periodic pattern. This allows for making predictions as to when a burst occurs. System providers can take advantage of such knowledge to reduce file-system contention by actively scheduling I/O bandwidth. The effectiveness of this approach, however, depends on the ability to detect and quantify the periodicity of I/O patterns online. In this paper, we introduce FTIO, an online method to detect periodic I/O phases, which is based on discrete Fourier transform (DFT), combined with outlier detection. We provide metrics that gauge the confidence in the output and tell how far from being periodic the signal is. We validate our approach with large-scale experiments on a production system and examine its limitations extensively. Our experiments show that FTIO has a mean error below 11%. Finally, we demonstrate that FTIO allowed the I/O scheduler Set- 10 to boost system utilization by 26% and reduce I/O slowdown by 56%.
format Preprint
id arxiv_https___arxiv_org_abs_2306_08601
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Capturing Periodic I/O Using Frequency Techniques
Tarraf, Ahmad
Bandet, Alexis
Boito, Francieli
Pallez, Guillaume
Wolf, Felix
Distributed, Parallel, and Cluster Computing
Many HPC applications perform their I/O in bursts that follow a periodic pattern. This allows for making predictions as to when a burst occurs. System providers can take advantage of such knowledge to reduce file-system contention by actively scheduling I/O bandwidth. The effectiveness of this approach, however, depends on the ability to detect and quantify the periodicity of I/O patterns online. In this paper, we introduce FTIO, an online method to detect periodic I/O phases, which is based on discrete Fourier transform (DFT), combined with outlier detection. We provide metrics that gauge the confidence in the output and tell how far from being periodic the signal is. We validate our approach with large-scale experiments on a production system and examine its limitations extensively. Our experiments show that FTIO has a mean error below 11%. Finally, we demonstrate that FTIO allowed the I/O scheduler Set- 10 to boost system utilization by 26% and reduce I/O slowdown by 56%.
title Capturing Periodic I/O Using Frequency Techniques
topic Distributed, Parallel, and Cluster Computing
url https://arxiv.org/abs/2306.08601