Long text generation, such as novel writing and discourse-level translation with extremely long contexts, presents significant challenges to current language models. Existing methods mainly focus on extending the model's context window through strategies like length extrapolation. However, these approaches demand substantial hardware resources during the training and/or inference phases. Our proposed method, Temp-Lora, introduces an alternative concept. Instead of relying on the KV cache to store all context information, we embeds this information directly into a temporary Lora module. In the process of long text generation, this module is progressively trained with text generated previously. This approach not only efficiently preserves contextual knowledge but also prevents any permanent alteration to the model's parameters given that the module is discarded post-generation. Extensive experiments on the PG19 language modeling benchmark and the GuoFeng discourse-level translation benchmark validate the effectiveness of Temp-Lora. Our results show that: 1) Temp-Lora substantially enhances generation quality for long text, as indicated by a 13.2% decrease in perplexity (PPL) on a subset of PG19, and a 29.3% decrease in PPL along with a 113.2% increase in BLEU score on a subset of GuoFeng, 2) Temp-Lora is compatible with and enhances most existing long text generation methods, and 3) Temp-Lora can greatly reduce computational costs by shortening the context window. For example, we can ensure a moderate improvement in generation quality (a decrease of 3.8% in PPL) while enabling a 51.5% memory usage reduction and a 60.0% decrease in latency for inference.
翻译:长文本生成,例如小说创作和超长上下文的篇章级翻译,给当前的语言模型带来了重大挑战。现有方法主要通过长度外推等策略来扩展模型的上下文窗口,但这些方法在训练和/或推理阶段需要大量硬件资源。我们提出的Temp-Lora方法引入了一个替代概念。该方法不依赖KV缓存来存储所有上下文信息,而是将这些信息直接嵌入到一个临时的Lora模块中。在长文本生成过程中,该模块会基于之前生成的文本逐步进行训练。这种方法不仅高效保留了上下文知识,而且由于该模块在生成后即被丢弃,因此不会对模型参数造成任何永久性改变。在PG19语言建模基准和GuoFeng篇章级翻译基准上的大量实验验证了Temp-Lora的有效性。我们的结果表明:1)Temp-Lora显著提升了长文本的生成质量,体现在PG19子集上困惑度(PPL)下降了13.2%,GuoFeng子集上困惑度下降了29.3%,同时BLEU分数提高了113.2%;2)Temp-Lora与大多数现有长文本生成方法兼容并能增强其性能;3)Temp-Lora通过缩短上下文窗口,能大幅降低计算成本。例如,我们可以在保证生成质量适度提升(困惑度降低3.8%)的同时,实现推理内存使用量减少51.5%和延迟降低60.0%。