BitMoD: Bit-serial Mixture-of-Datatype LLM Acceleration

Fuente: arXiv
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Main Authors: Chen, Yuzong, AbouElhamayed, Ahmed F., Dai, Xilai, Wang, Yang, Andronic, Marta, Constantinides, George A., Abdelfattah, Mohamed S.
Format: Preprint
Published: 2024
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author Chen, Yuzong
AbouElhamayed, Ahmed F.
Dai, Xilai
Wang, Yang
Andronic, Marta
Constantinides, George A.
Abdelfattah, Mohamed S.
author_facet Chen, Yuzong
AbouElhamayed, Ahmed F.
Dai, Xilai
Wang, Yang
Andronic, Marta
Constantinides, George A.
Abdelfattah, Mohamed S.
contents Large language models (LLMs) have demonstrated remarkable performance across various machine learning tasks. Yet the substantial memory footprint of LLMs significantly hinders their deployment. In this paper, we improve the accessibility of LLMs through BitMoD, an algorithm-hardware co-design solution that enables efficient LLM acceleration at low weight precision. On the algorithm side, BitMoD introduces fine-grained data type adaptation that uses a different numerical data type to quantize a group of (e.g., 128) weights. Through the careful design of these new data types, BitMoD is able to quantize LLM weights to very low precision (e.g., 4 bits and 3 bits) while maintaining high accuracy. On the hardware side, BitMoD employs a bit-serial processing element to easily support multiple numerical precisions and data types; our hardware design includes two key innovations: First, it employs a unified representation to process different weight data types, thus reducing the hardware cost. Second, it adopts a bit-serial dequantization unit to rescale the per-group partial sum with minimal hardware overhead. Our evaluation on six representative LLMs demonstrates that BitMoD significantly outperforms state-of-the-art LLM quantization and acceleration methods. For discriminative tasks, BitMoD can quantize LLM weights to 4-bit with $<\!0.5\%$ accuracy loss on average. For generative tasks, BitMoD is able to quantize LLM weights to 3-bit while achieving better perplexity than prior LLM quantization scheme. Combining the superior model performance with an efficient accelerator design, BitMoD achieves an average of $1.69\times$ and $1.48\times$ speedups compared to prior LLM accelerators ANT and OliVe, respectively.
format Preprint
id arxiv_https___arxiv_org_abs_2411_11745
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle BitMoD: Bit-serial Mixture-of-Datatype LLM Acceleration
Chen, Yuzong
AbouElhamayed, Ahmed F.
Dai, Xilai
Wang, Yang
Andronic, Marta
Constantinides, George A.
Abdelfattah, Mohamed S.
Machine Learning
Hardware Architecture
Large language models (LLMs) have demonstrated remarkable performance across various machine learning tasks. Yet the substantial memory footprint of LLMs significantly hinders their deployment. In this paper, we improve the accessibility of LLMs through BitMoD, an algorithm-hardware co-design solution that enables efficient LLM acceleration at low weight precision. On the algorithm side, BitMoD introduces fine-grained data type adaptation that uses a different numerical data type to quantize a group of (e.g., 128) weights. Through the careful design of these new data types, BitMoD is able to quantize LLM weights to very low precision (e.g., 4 bits and 3 bits) while maintaining high accuracy. On the hardware side, BitMoD employs a bit-serial processing element to easily support multiple numerical precisions and data types; our hardware design includes two key innovations: First, it employs a unified representation to process different weight data types, thus reducing the hardware cost. Second, it adopts a bit-serial dequantization unit to rescale the per-group partial sum with minimal hardware overhead. Our evaluation on six representative LLMs demonstrates that BitMoD significantly outperforms state-of-the-art LLM quantization and acceleration methods. For discriminative tasks, BitMoD can quantize LLM weights to 4-bit with $<\!0.5\%$ accuracy loss on average. For generative tasks, BitMoD is able to quantize LLM weights to 3-bit while achieving better perplexity than prior LLM quantization scheme. Combining the superior model performance with an efficient accelerator design, BitMoD achieves an average of $1.69\times$ and $1.48\times$ speedups compared to prior LLM accelerators ANT and OliVe, respectively.
title BitMoD: Bit-serial Mixture-of-Datatype LLM Acceleration
topic Machine Learning
Hardware Architecture
url https://arxiv.org/abs/2411.11745