Graphics Processing Units (GPUs) have rapidly evolved to enable energy-efficient data-parallel computing for a broad range of scientific areas. While GPUs achieve exascale performance at a stringent power budget, they are also susceptible to soft errors, often caused by high-energy particle strikes, that can significantly affect the application output quality. Understanding the resilience of general purpose GPU applications is the purpose of this study. To this end, it is imperative to explore the range of application output by injecting faults at all the potential fault sites. This problem is especially challenging because unlike CPU applications, which are mostly single-threaded, GPGPU applications can contain hundreds to thousands of threads, resulting in a tremendously large fault site space - in the order of billions even for some simple applications. In this paper, we present a systematic way to progressively prune the fault site space aiming to dramatically reduce the number of fault injections such that assessment for GPGPU application error resilience can be practical. The key insight behind our proposed methodology stems from the fact that GPGPU applications spawn a lot of threads, however, many of them execute the same set of instructions. Therefore, several fault sites are redundant and can bemore »
Optimizing Data Locality and Termination Criterion for t-SNE
The t-Distributed Stochastic Neighbor Embedding (t-SNE) is known to be a successful method at visualizing high-dimensional data, making it very popular in the machine-learning and data analysis community, especially recently. However, there are two glaring unaddressed problems: (a) Existing GPU accelerated implementations of t-SNE do not account for the poor data locality present in the computation. This results in sparse matrix computations being a bottleneck during execution, especially for large data sets. (b) Another problem is the lack of an effective stopping criterion in the literature. In this paper, we report an improved GPU implementation that uses sparse matrix re-ordering to improve t-SNE's memory access pattern and a novel termination criterion that is better suited for visualization purposes. The proposed methods result in up to 4.63 x end-to-end speedup and provide a practical stopping metric, potentially preventing the algorithm from terminating prematurely or running for an excessive amount of iterations. These developments enable high-quality visualizations and accurate analyses of complex large data sets containing up to 10 million data points and requiring thousands of iterations for convergence.
- Award ID(s):
- Publication Date:
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- Journal Name:
- 2021 International Joint Conference on Neural Networks (IJCNN)
- Sponsoring Org:
- National Science Foundation
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