Emergent Mind

LoCoCo: Dropping In Convolutions for Long Context Compression

(2406.05317)
Published Jun 8, 2024 in cs.LG and cs.CL

Abstract

This paper tackles the memory hurdle of processing long context sequences in LLMs, by presenting a novel approach, Dropping In Convolutions for Long Context Compression (LoCoCo). LoCoCo employs only a fixed-size Key-Value (KV) cache, and can enhance efficiency in both inference and fine-tuning stages. Diverging from prior methods that selectively drop KV pairs based on heuristics, LoCoCo leverages a data-driven adaptive fusion technique, blending previous KV pairs with incoming tokens to minimize the loss of contextual information and ensure accurate attention modeling. This token integration is achieved through injecting one-dimensional convolutional kernels that dynamically calculate mixing weights for each KV cache slot. Designed for broad compatibility with existing LLM frameworks, LoCoCo allows for straightforward "drop-in" integration without needing architectural modifications, while incurring minimal tuning overhead. Experiments demonstrate that LoCoCo maintains consistently outstanding performance across various context lengths and can achieve a high context compression rate during both inference and fine-tuning phases. During inference, we successfully compressed up to 3482 tokens into a 128-size KV cache, while retaining comparable performance to the full sequence - an accuracy improvement of up to 0.2791 compared to baselines at the same cache size. During post-training tuning, we also effectively extended the context length from 4K to 32K using a KV cache of fixed size 512, achieving performance similar to fine-tuning with entire sequences.

Overview

  • LoCoCo introduces an innovative approach using one-dimensional convolutional kernels to compress long context sequences in LLMs while maintaining a fixed-size KV cache for efficient memory usage.

  • The method supports adaptive token fusion and is designed for seamless integration with existing LLM frameworks without requiring architectural modifications, ensuring low tuning overhead.

  • Experimental results demonstrate LoCoCo's effectiveness in handling long contexts with comparable performance to full sequence processing across various tasks, including RACE, TriviaQA, and HellaSwag, while displaying superior memory efficiency and scalability.

LoCoCo: Dropping In Convolutions for Long Context Compression

The paper "LoCoCo: Dropping In Convolutions for Long Context Compression" presents a novel approach aimed at addressing the significant memory challenges in processing long context sequences within LLMs. The core innovation of this paper, termed LoCoCo, leverages a data-driven adaptive fusion technique utilizing one-dimensional convolutional kernels to dynamically compute the mixing weights for key-value (KV) cache slots. This specialized token integration enables LoCoCo to maintain an efficient fixed-size KV cache, which significantly enhances memory usage and ensures accurate attention modeling without the need for architectural modifications.

Key Contributions and Methodology

LoCoCo's primary contribution lies in its ability to compress long context sequences into manageable KV cache sizes, thus maintaining efficiency during both inference and fine-tuning stages. The paper outlines several methodological advancements:

  1. Adaptive Token Fusion: Unlike previous methods that rely on heuristic-based token dropping, LoCoCo employs one-dimensional convolutional kernels to dynamically calculate the mixing weights for KV cache slots. This approach ensures minimal loss of contextual information and allows for accurate attention modeling.
  2. Fixed-Size KV Cache: By maintaining a static-size KV cache, LoCoCo diverges from approaches that let the cache size increase linearly with context length. This strategy significantly reduces memory demands, making the method suitable for extensive sequences.
  3. Broad Compatibility and Ease of Integration: LoCoCo is designed to integrate seamlessly with existing LLM frameworks without necessitating any changes to the architectural design of the models. This "drop-in" characteristic ensures that the method incurs minimal tuning overhead while achieving high context compression rates.

Experimental Results

The experimental validation demonstrates LoCoCo's efficacy across various tasks and highlights its capacity to handle extensive contexts efficiently. Notably:

  • In the inference phase, LoCoCo successfully compressed up to 3482 tokens into a KV cache size of 128 while retaining comparable performance to processing the full sequence. This led to an accuracy improvement of up to 0.2791 compared to baseline methods under the same cache size.
  • During fine-tuning, LoCoCo extended the context length from 4K to 32K using a static-size KV cache of 512, obtaining performance akin to fine-tuning with the entire sequence length.

The experiments also included evaluations on multiple downstream tasks, such as RACE, TriviaQA, and HellaSwag, showing superior performance over existing state-of-the-art methods. Additionally, the model demonstrated robustness in its memory usage and throughput, ensuring practical applicability for efficient long-context processing.

Implications and Future Developments

The implications of LoCoCo are significant for both practical and theoretical applications in AI:

  • Memory Efficiency: By addressing the KV cache's growing memory demands, LoCoCo enables the deployment of LLMs in memory-constrained environments, such as edge computing devices.
  • Scalability: The method augments the scalability of LLMs, allowing them to process significantly longer sequences without corresponding increases in computational or memory resources.
  • Flexibility and Integration: LoCoCo’s ease of integration with existing models ensures that it can be widely adopted without extensive re-engineering of current systems, facilitating faster deployment in production environments.

Looking forward, LoCoCo opens avenues for further research in adaptive token compression techniques and their impact on LLM performance. Future research could explore hybrid approaches that combine convolutional token integration with other memory-efficient strategies, such as landmark attention mechanisms or token pruning methods, to further enhance context handling capabilities.

Conclusion

"LoCoCo: Dropping In Convolutions for Long Context Compression" provides a robust framework for efficiently managing long context sequences in LLMs. By utilizing adaptive convolutional token fusion, LoCoCo maintains a fixed-size KV cache, thereby addressing the substantial memory challenges inherent in long-context processing. The method’s compatibility with existing LLM architectures and its impressive performance across various tasks underscore its potential for broad applicability in both research and real-world applications.

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