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arXiv · 1811.01564

Parallel training of linear models without compromising convergence

Nikolas Ioannou·Celestine Dünner·Kornilios Kourtis·Thomas Parnell
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Abstract

In this paper we analyze, evaluate, and improve the performance of training generalized linear models on modern CPUs. We start with a state-of-the-art asynchronous parallel training algorithm, identify system-level performance bottlenecks, and apply optimizations that improve data parallelism, cache line locality, and cache line prefetching of the algorithm. These modifications reduce the per-epoch run-time significantly, but take a toll on algorithm convergence in terms of the required number of epochs. To alleviate these shortcomings of our systems-optimized version, we propose a novel, dynamic data partitioning scheme across threads which allows us to approach the convergence of the sequential version. The combined set of optimizations result in a consistent bottom line speedup in convergence of up to 12x compared to the initial asynchronous parallel training algorithm and up to 42x, compared to state of the art implementations (scikit-learn and h2o) on a range of multi-core CPU architectures.

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Nikolas Ioannou, Celestine Dünner, Kornilios Kourtis, Thomas Parnell. 2018-11-05. Parallel training of linear models without compromising convergence. https://arxiv.org/abs/1811.01564

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