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Main Authors: Alama, Youssef A. Ait, Sakpal, Sampada, Wang, Ke, Bunescu, Razvan, Karanth, Avinash, Louri, Ahmed
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2412.16208
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author Alama, Youssef A. Ait
Sakpal, Sampada
Wang, Ke
Bunescu, Razvan
Karanth, Avinash
Louri, Ahmed
author_facet Alama, Youssef A. Ait
Sakpal, Sampada
Wang, Ke
Bunescu, Razvan
Karanth, Avinash
Louri, Ahmed
contents Hardware failures are a growing challenge for machine learning accelerators, many of which are based on systolic arrays. When a permanent hardware failure occurs in a systolic array, existing solutions include localizing and isolating the faulty processing element (PE), using a redundant PE for re-execution, or in some extreme cases decommissioning the entire accelerator for further investigation. In this paper, we propose novel algorithmic approaches that mitigate permanent hardware faults in neural network (NN) accelerators by uniquely integrating the behavior of the faulty component instead of bypassing it. In doing so, we aim for a more sustainable use of the accelerator where faulty hardware is neither bypassed nor discarded, instead being given a second life. We first introduce a CUDA-accelerated systolic array simulator in PyTorch, which enabled us to quantify the impact of permanent faults appearing on links connecting two PEs or in weight registers, where one bit is stuck at 0 or 1 in the float32, float16, or bfloat16 representation. We then propose several algorithmic mitigation techniques for a subset of stuck-at faults, such as Invertible Scaling or Shifting of activations and weights, or fine tuning with the faulty behavior. Notably, the proposed techniques do not require any hardware modification, instead relying on existing components of widely used systolic array based accelerators, such as normalization, activation, and storage units. Extensive experimental evaluations using fully connected and convolutional NNs trained on MNIST, CIFAR-10 and ImageNet show that the proposed fault-tolerant approach matches or gets very close to the original fault-free accuracy.
format Preprint
id arxiv_https___arxiv_org_abs_2412_16208
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Algorithmic Strategies for Sustainable Reuse of Neural Network Accelerators with Permanent Faults
Alama, Youssef A. Ait
Sakpal, Sampada
Wang, Ke
Bunescu, Razvan
Karanth, Avinash
Louri, Ahmed
Machine Learning
Hardware Architecture
Hardware failures are a growing challenge for machine learning accelerators, many of which are based on systolic arrays. When a permanent hardware failure occurs in a systolic array, existing solutions include localizing and isolating the faulty processing element (PE), using a redundant PE for re-execution, or in some extreme cases decommissioning the entire accelerator for further investigation. In this paper, we propose novel algorithmic approaches that mitigate permanent hardware faults in neural network (NN) accelerators by uniquely integrating the behavior of the faulty component instead of bypassing it. In doing so, we aim for a more sustainable use of the accelerator where faulty hardware is neither bypassed nor discarded, instead being given a second life. We first introduce a CUDA-accelerated systolic array simulator in PyTorch, which enabled us to quantify the impact of permanent faults appearing on links connecting two PEs or in weight registers, where one bit is stuck at 0 or 1 in the float32, float16, or bfloat16 representation. We then propose several algorithmic mitigation techniques for a subset of stuck-at faults, such as Invertible Scaling or Shifting of activations and weights, or fine tuning with the faulty behavior. Notably, the proposed techniques do not require any hardware modification, instead relying on existing components of widely used systolic array based accelerators, such as normalization, activation, and storage units. Extensive experimental evaluations using fully connected and convolutional NNs trained on MNIST, CIFAR-10 and ImageNet show that the proposed fault-tolerant approach matches or gets very close to the original fault-free accuracy.
title Algorithmic Strategies for Sustainable Reuse of Neural Network Accelerators with Permanent Faults
topic Machine Learning
Hardware Architecture
url https://arxiv.org/abs/2412.16208