  This paper introduces PowerInfer, a high-speed Large Language Model (LLM)
inference engine on a personal computer (PC) equipped with a single
consumer-grade GPU. The key underlying the design of PowerInfer is exploiting
the high locality inherent in LLM inference, characterized by a power-law
distribution in neuron activation. This distribution indicates that a small
subset of neurons, termed hot neurons, are consistently activated across
inputs, while the majority, cold neurons, vary based on specific inputs.
PowerInfer exploits such an insight to design a GPU-CPU hybrid inference
engine: hot-activated neurons are preloaded onto the GPU for fast access, while
cold-activated neurons are computed on the CPU, thus significantly reducing GPU
memory demands and CPU-GPU data transfers. PowerInfer further integrates
adaptive predictors and neuron-aware sparse operators, optimizing the
efficiency of neuron activation and computational sparsity. Evaluation shows
that PowerInfer attains an average token generation rate of 13.20 tokens/s,
with a peak of 29.08 tokens/s, across various LLMs (including OPT-175B) on a
single NVIDIA RTX 4090 GPU, only 18% lower than that achieved by a top-tier
server-grade A100 GPU. This significantly outperforms llama.cpp by up to 11.69x
while retaining model accuracy.
