TENET: An Efficient Sparsity-Aware LUT-Centric Architecture for Ternary LLM Inference On Edge

Abstract: Ternary quantization has emerged as a powerful technique for reducing both computational and memory footprint of LLMs (LLM), enabling efficient real-time inference deployment without significantly compromising model accuracy. Conventional LLM inference platforms (e.g GPUs) cannot capitalize on its benefits, as they (i) lack native support for ternary arithmetic and memory specialization and (ii) remain severely under-utilized in low-batch, real-time scenarios. In this work, we propose TENET, a sparse-aware LUT-centric architecture that co-optimizes algorithm, compute, and memory for ternary LLM inference. To maximize the efficiency of Ternary Linear layer, TENET introduces a Sparse Ternary LUT (STL) core that optimizes ternary mixed-precision GEMM using a symmetric precompute lookup table. It also features Dynamic Activation N:M Sparsity to exploit the sparsity within the activation of each token. Additionally, we propose a LUT-based 64B:80B ternary weight decompression module to fully exploit the memory efficiency of ternary values. At the system level, we design a heterogeneous TENET accelerator with full programmability that integrates STL cores with high-precision cores. An associated Linear-Projection-aware Sparse Attention dataflow is introduced to optimize memory access and hardware utilization. We implement TENET accelerator prototype on both FPGA and ASIC platforms. Experiments across various model sizes and workloads demonstrate that TENET-FPGA and TENET-ASIC improve energy efficiency by 4.3$\times$ and 21.1$\times$, respectively, compared to the A100 GPU. Furthermore, TENET-ASIC achieves a 2.7$\times$ average speedup compared to the A100 GPU in end-to-end inference latency.