"Give Me BF16 or Give Me Death"? Accuracy-Performance Trade-Offs in LLM Quantization

Fuente: arXiv
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Autori principali: Kurtic, Eldar, Marques, Alexandre, Pandit, Shubhra, Kurtz, Mark, Alistarh, Dan
Natura: Preprint
Pubblicazione: 2024
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author Kurtic, Eldar
Marques, Alexandre
Pandit, Shubhra
Kurtz, Mark
Alistarh, Dan
author_facet Kurtic, Eldar
Marques, Alexandre
Pandit, Shubhra
Kurtz, Mark
Alistarh, Dan
contents Quantization is a powerful tool for accelerating large language model (LLM) inference, but the accuracy-performance trade-offs across different formats remain unclear. In this paper, we conduct the most comprehensive empirical study to date, evaluating FP8, INT8, and INT4 quantization across academic benchmarks and real-world tasks on the entire Llama-3.1 model family. Through over 500,000 evaluations, our investigation yields several key findings: (1) FP8 (W8A8-FP) is effectively lossless across all model scales, (2) well-tuned INT8 (W8A8-INT) achieves surprisingly low (1-3\%) accuracy degradation, and (3) INT4 weight-only (W4A16-INT) is more competitive than expected, rivaling 8-bit quantization. Further, we investigate the optimal quantization format for different deployments by analyzing inference performance through the popular vLLM framework. Our analysis provides clear deployment recommendations: W4A16 is the most cost-efficient for synchronous setups, while W8A8 dominates in asynchronous continuous batching. For mixed workloads, the optimal choice depends on the specific use case. Our findings offer practical, data-driven guidelines for deploying quantized LLMs at scale -- ensuring the best balance between speed, efficiency, and accuracy.
format Preprint
id arxiv_https___arxiv_org_abs_2411_02355
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle "Give Me BF16 or Give Me Death"? Accuracy-Performance Trade-Offs in LLM Quantization
Kurtic, Eldar
Marques, Alexandre
Pandit, Shubhra
Kurtz, Mark
Alistarh, Dan
Machine Learning
Artificial Intelligence
Quantization is a powerful tool for accelerating large language model (LLM) inference, but the accuracy-performance trade-offs across different formats remain unclear. In this paper, we conduct the most comprehensive empirical study to date, evaluating FP8, INT8, and INT4 quantization across academic benchmarks and real-world tasks on the entire Llama-3.1 model family. Through over 500,000 evaluations, our investigation yields several key findings: (1) FP8 (W8A8-FP) is effectively lossless across all model scales, (2) well-tuned INT8 (W8A8-INT) achieves surprisingly low (1-3\%) accuracy degradation, and (3) INT4 weight-only (W4A16-INT) is more competitive than expected, rivaling 8-bit quantization. Further, we investigate the optimal quantization format for different deployments by analyzing inference performance through the popular vLLM framework. Our analysis provides clear deployment recommendations: W4A16 is the most cost-efficient for synchronous setups, while W8A8 dominates in asynchronous continuous batching. For mixed workloads, the optimal choice depends on the specific use case. Our findings offer practical, data-driven guidelines for deploying quantized LLMs at scale -- ensuring the best balance between speed, efficiency, and accuracy.
title "Give Me BF16 or Give Me Death"? Accuracy-Performance Trade-Offs in LLM Quantization
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2411.02355