FP6-LLM: Efficiently Serving Large Language Models Through FP6-Centric
  Algorithm-System Co-Design
Authors: name: Haojun Xia; name: Zhen Zheng; name: Xiaoxia Wu; name: Shiyang Chen; name: Zhewei Yao; name: Stephen Youn; name: Arash Bakhtiari; name: Michael Wyatt; name: Donglin Zhuang; name: Zhongzhu Zhou; name: Olatunji Ruwase; name: Yuxiong He; name: Shuaiwen Leon Song
Published: 2024-01-25 11:46:38

Abstract: Six-bit quantization (FP6) can effectively reduce the size of large language
models (LLMs) and preserve the model quality consistently across varied
applications. However, existing systems do not provide Tensor Core support for
FP6 quantization and struggle to achieve practical performance improvements
during LLM inference. It is challenging to support FP6 quantization on GPUs due
to (1) unfriendly memory access of model weights with irregular bit-width and
(2) high runtime overhead of weight de-quantization. To address these problems,
we propose TC-FPx, the first full-stack GPU kernel design scheme with unified
Tensor Core support of float-point weights for various quantization bit-width.
We integrate TC-FPx kernel into an existing inference system, providing new
end-to-end support (called FP6-LLM) for quantized LLM inference, where better
trade-offs between inference cost and model quality are achieved. Experiments
show that FP6-LLM enables the inference of LLaMA-70b using only a single GPU,
achieving 1.69x-2.65x higher normalized inference throughput than the FP16
baseline. The source code will be publicly available soon.