HyDra: SOT-CAM Based Vector Symbolic Macro for Hyperdimensional Computing

Fuente: arXiv
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Autori principali: Nayan, Md Mizanur Rahaman, Liu, Che-Kai, Wan, Zishen, Raychowdhury, Arijit, Naeemi, Azad J
Natura: Preprint
Pubblicazione: 2025
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author Nayan, Md Mizanur Rahaman
Liu, Che-Kai
Wan, Zishen
Raychowdhury, Arijit
Naeemi, Azad J
author_facet Nayan, Md Mizanur Rahaman
Liu, Che-Kai
Wan, Zishen
Raychowdhury, Arijit
Naeemi, Azad J
contents Hyperdimensional computing (HDC) is a brain-inspired paradigm valued for its noise robustness, parallelism, energy efficiency, and low computational overhead. Hardware accelerators are being explored to further enhance their performance, but current solutions are often limited by application specificity and the latency of encoding and similarity search. This paper presents a generalized, reconfigurable on-chip training and inference architecture for HDC, utilizing spin-orbit-torque magnetic random access memory (SOT-MRAM) based content-addressable memory (SOT-CAM). The proposed SOT-CAM array integrates storage and computation, enabling in-memory execution of key HDC operations: binding (bitwise multiplication), permutation (bit shfiting), and efficient similarity search. Furthermore, a novel bit drop method-based permutation backed by holographic information representation of HDC is proposed which replaces conventional permutation execution in hardware resulting in a 6x latency improvement, and an HDC-specific adder reduces energy and area by 1.51X and 1.43x, respectively. To mitigate the parasitic effect of interconnects in the similarity search, a four-stage voltage scaling scheme has been proposed to ensure an accurate representation of the Hamming distance. Benchmarked at 7nm, the architecture achieves energy reductions of 21.5x, 552.74x, 1.45x, and 282.57x for addition, permutation, multiplication, and search operations, respectively, compared to CMOS-based HDC. Against state-of-the-art HDC accelerators, it achieves a 2.27x lower energy consumption and outperforms CPU and eGPU implementations by 2702x and 23161x, respectively, with less than 3% drop in accuracy.
format Preprint
id arxiv_https___arxiv_org_abs_2504_14020
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle HyDra: SOT-CAM Based Vector Symbolic Macro for Hyperdimensional Computing
Nayan, Md Mizanur Rahaman
Liu, Che-Kai
Wan, Zishen
Raychowdhury, Arijit
Naeemi, Azad J
Emerging Technologies
Hyperdimensional computing (HDC) is a brain-inspired paradigm valued for its noise robustness, parallelism, energy efficiency, and low computational overhead. Hardware accelerators are being explored to further enhance their performance, but current solutions are often limited by application specificity and the latency of encoding and similarity search. This paper presents a generalized, reconfigurable on-chip training and inference architecture for HDC, utilizing spin-orbit-torque magnetic random access memory (SOT-MRAM) based content-addressable memory (SOT-CAM). The proposed SOT-CAM array integrates storage and computation, enabling in-memory execution of key HDC operations: binding (bitwise multiplication), permutation (bit shfiting), and efficient similarity search. Furthermore, a novel bit drop method-based permutation backed by holographic information representation of HDC is proposed which replaces conventional permutation execution in hardware resulting in a 6x latency improvement, and an HDC-specific adder reduces energy and area by 1.51X and 1.43x, respectively. To mitigate the parasitic effect of interconnects in the similarity search, a four-stage voltage scaling scheme has been proposed to ensure an accurate representation of the Hamming distance. Benchmarked at 7nm, the architecture achieves energy reductions of 21.5x, 552.74x, 1.45x, and 282.57x for addition, permutation, multiplication, and search operations, respectively, compared to CMOS-based HDC. Against state-of-the-art HDC accelerators, it achieves a 2.27x lower energy consumption and outperforms CPU and eGPU implementations by 2702x and 23161x, respectively, with less than 3% drop in accuracy.
title HyDra: SOT-CAM Based Vector Symbolic Macro for Hyperdimensional Computing
topic Emerging Technologies
url https://arxiv.org/abs/2504.14020