LLM in a flash: Efficient Large Language Model Inference with Limited
  Memory
Authors: name: Keivan Alizadeh; name: Iman Mirzadeh; name: Dmitry Belenko; name: Karen Khatamifard; name: Minsik Cho; name: Carlo C Del Mundo; name: Mohammad Rastegari; name: Mehrdad Farajtabar
Published: 2023-12-12 18:57:08

Abstract: Large language models (LLMs) are central to modern natural language
processing, delivering exceptional performance in various tasks. However, their
intensive computational and memory requirements present challenges, especially
for devices with limited DRAM capacity. This paper tackles the challenge of
efficiently running LLMs that exceed the available DRAM capacity by storing the
model parameters on flash memory but bringing them on demand to DRAM. Our
method involves constructing an inference cost model that harmonizes with the
flash memory behavior, guiding us to optimize in two critical areas: reducing
the volume of data transferred from flash and reading data in larger, more
contiguous chunks. Within this flash memory-informed framework, we introduce
two principal techniques. First, "windowing'" strategically reduces data
transfer by reusing previously activated neurons, and second, "row-column
bundling", tailored to the sequential data access strengths of flash memory,
increases the size of data chunks read from flash memory. These methods
collectively enable running models up to twice the size of the available DRAM,
with a 4-5x and 20-25x increase in inference speed compared to naive loading
approaches in CPU and GPU, respectively. Our integration of sparsity awareness,
context-adaptive loading, and a hardware-oriented design paves the way for
effective inference of LLMs on devices with limited memory.