DeFT: Decoding with Flash Tree-attention for Efficient Tree-structured LLM Inference
On the map: Efficient LLM inference and serving → KV cache optimization
Abstract (arXiv)
Large language models (LLMs) are increasingly employed for complex tasks that process multiple generation calls in a tree structure with shared prefixes of tokens, including few-shot prompting, multi-step reasoning, speculative decoding, etc. However, existing inference systems for tree-based applications are inefficient due to improper partitioning of queries and KV cache during attention calculation. This leads to two main issues: (1) a lack of memory access (IO) reuse for KV cache of shared prefixes, and (2) poor load balancing.As a result, there is redundant KV cache IO between GPU global memory and shared memory, along with low GPU utilization. To address these challenges, we propose DeFT(Decoding with Flash Tree-Attention), a hardware-efficient attention algorithm with prefix-aware and load-balanced KV cache partitions. DeFT reduces the number of read/write operations of KV cache during attention calculation through KV-Guided Grouping, a method that avoids repeatedly loading KV cache of shared prefixes in attention computation. Additionally, we propose Flattened Tree KV Splitting, a mechanism that ensures even distribution of the KV cache across partitions with little computation redundancy, enhancing GPU utilization during attention computations. By reducing 73-99% KV cache IO and nearly 100% IO for partial results during attention calculation, DeFT achieves up to 2.23/3.59x speedup in the end-to-end/attention latency across three practical tree-based workloads compared to state-of-the-art attention algorithms. Our code is available at https://github.com/LINs-lab/DeFT.
Key facts. Cited by 19 papers in the map (data through 14 Oct 2026). Placed in KV cache optimization, one of 12 directions in Efficient LLM inference and serving. Builds on 36 of its 48 references that are in the map. First posted on arXiv 30 Mar 2024.
Builds on
36 of 48 references.
Closest ancestors · 3
Same direction, newest first
- 2024Bifurcated Attention: Accelerating Massively Parallel Decoding with Shared Prefixes in LLMs13 Mar
- 2024ChunkAttention: Efficient Self-Attention with Prefix-Aware KV Cache and Two-Phase Partition23 Feb
- 2023Efficient Memory Management for Large Language Model Serving with PagedAttention12 Sep
Other references · 33
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- 2019HuggingFace's Transformers: State-of-the-art Natural Language Processingcited by 2,218
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- 2019Plug and Play Language Models: A Simple Approach to Controlled Text Generationcited by 799
- 2019Fast Transformer Decoding: One Write-Head is All You Needcited by 717
- 2020Recipes for building an open-domain chatbotcited by 593
- 2023SqueezeLLM: Dense-and-Sparse Quantizationcited by 294
- 2023Prompt Cache: Modular Attention Reuse for Low-Latency Inferencecited by 268
- 2017Lexically Constrained Decoding for Sequence Generation Using Grid Beam Searchcited by 237
- 2023Self-Evaluation Guided Beam Search for Reasoningcited by 196
- 2018Fast Lexically Constrained Decoding with Dynamic Beam Allocation for Neural Machine Translationcited by 182
- 2021NeuroLogic A*esque Decoding: Constrained Text Generation with Lookahead Heuristicscited by 154
- 2020NeuroLogic Decoding: (Un)supervised Neural Text Generation with Predicate Logic Constraintscited by 149
- 2018Learning to Write with Cooperative Discriminatorscited by 119
- 2016Guided Open Vocabulary Image Captioning with Constrained Beam Searchcited by 105
- 2024Hydragen: High-Throughput LLM Inference with Shared Prefixescited by 73
- 2022NaturalProver: Grounded Mathematical Proof Generation with Language Modelscited by 72
- 2023FlashDecoding++: Faster Large Language Model Inference on GPUscited by 71
- 2023Lookahead: An Inference Acceleration Framework for Large Language Model with Lossless Generation Accuracycited by 37
- 2024APAR: LLMs Can Do Auto-Parallel Auto-Regressive Decodingcited by 24
- 2024RelayAttention for Efficient Large Language Model Serving with Long System Promptscited by 13
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Citing papers per year: 2024: 1; 2025: 6; 2026: 12.
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- 2024A Survey on Large Language Model Acceleration based on KV Cache Managementcited by 131
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- 2026AREAL-DTA: Dynamic Tree Attention for Efficient Reinforcement Learning of Large Language Models31 Jan 2026
- 2026Even GPT-5.2 Can't Count to Five: The Case for Zero-Error Horizons in Trustworthy LLMs22 Jan 2026
- 2026RadixMLP -- Intra-batch Deduplication for Causal Transformers21 Jan 2026
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- 2025TyphoonMLA: A Mixed Naive-Absorb MLA Kernel For Shared Prefix25 Sep 2025
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- 2025CoDec: Prefix-Shared Decoding Kernel for LLMs23 May 2025
- 2025Generative AI Act II: Test Time Scaling Drives Cognition Engineering18 Apr 2025
- 2025FR-Spec: Accelerating Large-Vocabulary Language Models via Frequency-Ranked Speculative Sampling20 Feb 2025
- 2025A Survey on LLM Test-Time Compute via Search: Tasks, LLM Profiling, Search Algorithms, and Relevant Frameworks17 Jan 2025
- 2024A Survey on Large Language Model Acceleration based on KV Cache Management27 Dec 2024
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- 2026PaDoc: Layout-Grounded Parallel Decoding for Document Parsingcited by 1
- 2026Intra-Prompt Parallel Decoding for Common-Context Question Answeringcited by 1
- 2026Requests of a Feather Must Flock Together: Batch Size vs. Prefix Homogeneity in LLM Inferencecited by 0
- 2026LumoTree: Path-Parallel Speculative Verification for Hybrid Language Modelscited by 0
- 2026LumoTree: Path-Parallel Speculative Verification for Hybrid Language Models20 Sep 2026
- 2026Intra-Prompt Parallel Decoding for Common-Context Question Answering4 Sep 2026
- 2026PaDoc: Layout-Grounded Parallel Decoding for Document Parsing6 Aug 2026
- 2026Bole: Efficient Tree Speculation for Hybrid-Attention Language Models3 Aug 2026
- 2026D^2SD: Accelerating Speculative Decoding with Dual Diffusion Draft Models3 Jun 2026
- 2026Requests of a Feather Must Flock Together: Batch Size vs. Prefix Homogeneity in LLM Inference7 May 2026
- 2026MAC-Attention: a Match-Amend-Complete Scheme for Fast and Accurate Attention Computation31 Mar 2026
- 2026TALON: Confidence-Aware Speculative Decoding with Adaptive Token Trees12 Jan 2026
- 2025FR-Spec: Accelerating Large-Vocabulary Language Models via Frequency-Ranked Speculative Sampling20 Feb 2025
- 2025Saffron-1: Safety Inference Scalingcited by 1
- 2025Saffron-1: Safety Inference Scaling6 Jun 2025
- 2025CoDec: Prefix-Shared Decoding Kernel for LLMscited by 4
- 2026Even GPT-5.2 Can't Count to Five: The Case for Zero-Error Horizons in Trustworthy LLMscited by 1
- 2026AREAL-DTA: Dynamic Tree Attention for Efficient Reinforcement Learning of Large Language Modelscited by 1
- 2025TyphoonMLA: A Mixed Naive-Absorb MLA Kernel For Shared Prefixcited by 0
- 2026RadixMLP -- Intra-batch Deduplication for Causal Transformerscited by 0
- 2026Mahalanobis-Based Multi-Head Attention for Complex State Propagationcited by 0
- 2026Mahalanobis-Based Multi-Head Attention for Complex State Propagation25 Aug 2026
- 2026AREAL-DTA: Dynamic Tree Attention for Efficient Reinforcement Learning of Large Language Models31 Jan 2026
- 2026Even GPT-5.2 Can't Count to Five: The Case for Zero-Error Horizons in Trustworthy LLMs22 Jan 2026
- 2026RadixMLP -- Intra-batch Deduplication for Causal Transformers21 Jan 2026
- 2025TyphoonMLA: A Mixed Naive-Absorb MLA Kernel For Shared Prefix25 Sep 2025
- 2025CoDec: Prefix-Shared Decoding Kernel for LLMs23 May 2025
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