In plain words: It stretches how a model tracks token positions by unevenly rescaling them, then fine-tunes in stages so short-trained models can read longer texts. This reached a 2 million-token window with 1,000 fine-tuning steps on texts under 256k, without losing short-text performance.
Abstract · LongRoPE: Extending LLM Context Window Beyond 2 Million Tokens
Large context window is a desirable feature in large language models (LLMs). However, due to high fine-tuning costs, scarcity of long texts, and catastrophic values introduced by new token positions, current extended context windows are limited to around 128k tokens. This paper introduces LongRoPE that, for the first time, extends the context window of pre-trained LLMs to an impressive 2048k tokens, with up to only 1k fine-tuning steps at within 256k training lengths, while maintaining performance at the original short context window. This is achieved by three key innovations: (i) we identify and exploit two forms of non-uniformities in positional interpolation through an efficient search, providing a better initialization for fine-tuning and enabling an 8x extension in non-fine-tuning scenarios; (ii) we introduce a progressive extension strategy that first fine-tunes a 256k length LLM and then conducts a second positional interpolation on the fine-tuned extended LLM to achieve a 2048k context window; (iii) we readjust LongRoPE on 8k length to recover the short context window performance. Extensive experiments on LLaMA2 and Mistral across various tasks demonstrate the effectiveness of our method. Models extended via LongRoPE retain the original architecture with minor modifications to the positional embedding, and can reuse most pre-existing optimizations.
Yiran Ding, Li Lyna Zhang, Chengruidong Zhang, Yuanyuan Xu, Ning Shang, Jiahang Xu, Fan Yang, Mao Yang
arXiv:2402.13753 · cs.CL · submitted Feb 21, 2024
abstract · pdf · html
I know people complain about hardware and compute resources. But, this is like complaining about Python resource usage in the early 90's. The development complexity & resources is far more expensive than chips on the long run. I am personally re-organizing my AI organization to move away from complex RAG setups and get comfortable with long-context workflows.
Just to be clear - I also think that inference-optimized chips are the next frontier - Nvidia GPUs were designed & built in a different age than what’s going on now.