LLM.int8(): 8-bit Matrix Multiplication for Transformers at Scale
Authors: Tim Dettmers, Mike Lewis, Younes Belkada, Luke Zettlemoyer
AI-generated Key Points
- Large language models have revolutionized natural language processing but require significant GPU memory for inference
- LLM.int8() is a procedure developed by researchers to address this issue
- LLM.int8() cuts the memory needed for inference by half while retaining full precision performance
- The researchers were able to load a 175B parameter checkpoint, convert it to Int8, and use it immediately without any performance degradation
- LLM.int8() uses a two-part quantization procedure using vector-wise quantization with separate normalization constants for each inner product in the matrix multiplication to quantize most of the features
- For emergent outliers, a new mixed-precision decomposition scheme isolates outlier feature dimensions into a 16-bit matrix multiplication while still more than 99.9% of values are multiplied in 8-bit
- Outlier features were defined based on their magnitude compared to other features within the model and analyzed for their effect on model performance
- LLM.int8() makes large language models more accessible by reducing GPU memory requirements during inference
Abstract: Large language models have been widely adopted but require significant GPU memory for inference. We develop a procedure for Int8 matrix multiplication for feed-forward and attention projection layers in transformers, which cut the memory needed for inference by half while retaining full precision performance. With our method, a 175B parameter 16/32-bit checkpoint can be loaded, converted to Int8, and used immediately without performance degradation. This is made possible by understanding and working around properties of highly systematic emergent features in transformer language models that dominate attention and transformer predictive performance. To cope with these features, we develop a two-part quantization procedure, LLM.int8(). We first use vector-wise quantization with separate normalization constants for each inner product in the matrix multiplication, to quantize most of the features. However, for the emergent outliers, we also include a new mixed-precision decomposition scheme, which isolates the outlier feature dimensions into a 16-bit matrix multiplication while still more than 99.9% of values are multiplied in 8-bit. Using LLM.int8(), we show empirically it is possible to perform inference in LLMs with up to 175B parameters without any performance degradation. This result makes such models much more accessible, for example making it possible to use OPT-175B/BLOOM on a single server with consumer GPUs.
Tools for this paper
Ask questions about this paper to our AI assistant
You can also chat with multiple papers at once here.
The previous summary was created more than a year ago and can be re-run (if necessary) by clicking on the Run button below.
Similar papers summarized with our AI tools
Navigate through even more similar papers through a
tree representationLook for similar papers (in beta version)
We compare the title and abstract with papers indexed in our database. For arXiv papers, we search within the same category; for DOI and other sources, we search across sources and subjects. You can rerun the search as our database grows.
Disclaimer: The AI-based summarization tool and virtual assistant provided on this website may not always provide accurate and complete summaries or responses. We encourage you to carefully review and evaluate the generated content to ensure its quality and relevance to your needs.