一句话:提出 Mugi 架构,将值级并行推广到 LLM 非线性与不对称小批量 GEMM,显著提升吞吐与能效。
已有值级并行(VLP)主要面向大批量、低精度的对称激活-权重 GEMM,难以覆盖 LLM 中更复杂的运算。本文探索 VLP 对 LLM 的收益:首先将 VLP 推广到非线性近似,采用以值为中心的策略,为重要数值分配更高精度,从而在端到端 LLM 精度、性能和效率上优于现有非线性近似;其次针对小批量、非对称输入的 GEMM 优化 VLP,并结合权重仅量化、KV cache 量化和分组查询注意力等 LLM 优化。在此基础上设计 Mugi 架构,支持完整 LLM 工作负载。实验表明,Mugi 对非线性 softmax 操作的吞吐和能效最高提升 45 倍与 668 倍,对 LLM 整体提升 2.07 倍与 3.11 倍,并将运营碳排降低 1.45 倍、隐含碳排降低 1.48 倍。
Value level parallelism (VLP) has been proposed to improve the efficiency of large-batch, low-precision general matrix multiply (GEMM) between symmetric activations and weights. In transformer based large language models (LLMs), there exist more sophisticated operations beyond activation-weight GEMM. In this paper, we explore how VLP benefits LLMs. First, we generalize VLP for nonlinear approximations, outperforming existing nonlinear approximations in end-to-end LLM accuracy, performance, and efficiency. Our VLP approximation follows a value-centric approach, where important values are assigned with greater accuracy. Second, we optimize VLP for small-batch GEMMs with asymmetric inputs efficiently, which leverages timely LLM optimizations, including weight-only quantization, key-value (KV) cache quantization, and group query attention. Finally, we design a new VLP architecture, Mugi, to encapsulate the innovations above and support full LLM workloads, while providing better performance, efficiency and sustainability. Our experimental results show that Mugi can offer significant improvements on throughput and energy efficiency, up to 45× and 668× for nonlinear softmax operations, and 2.07× and 3.11× for LLMs, and also decrease operational carbon for LLM operation by 1.45× and embodied carbon by 1.48×.