Adaptive Layer-skipping in Pre-trained LLMs
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Abstract (arXiv)
Various layer-skipping methods have been proposed to accelerate token generation in large language models (LLMs). However, limited attention has been paid to a fundamental question: How do computational demands vary across the generation of different tokens? In this work, we introduce FlexiDepth, a method that dynamically adjusts the number of Transformer layers used in text generation. By incorporating a plug-in router and adapter, FlexiDepth enables adaptive computation in LLMs without modifying their original parameters. Applied to Llama-3-8B, it skips 8 out of 32 layers while maintaining full benchmark performance. Our experiments reveal that computational demands in LLMs significantly vary based on token type. Specifically, generating repetitive tokens or fixed phrases requires fewer layers, whereas producing tokens involving computation or high uncertainty requires more layers. Despite the computational savings, FlexiDepth does not yet achieve wall-clock speedup due to varied skipping patterns and I/O overhead. To inspire future work and advance research on practical speedup, we open-sourced FlexiDepth and a dataset documenting its layer allocation patterns.
Key facts. Cited by 24 papers in the map (data through 7 Oct 2026). Builds on 37 of its 46 references that are in the map. First posted on arXiv 31 Mar 2025.
Builds on
37 of 46 references.
References · 37
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- 2024Duo-LLM: A Framework for Studying Adaptive Computation in Large Language Modelscited by 6
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Citing papers per year: 2025: 10; 2026: 14.
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- 2025Think-at-Hard: Dynamic Looped Transformers for Improved Reasoningcited by 12
- 2025Dr.LLM: Dynamic Layer Routing in LLMscited by 10
- 2026DySL-VLA: Efficient Vision-Language-Action Model Inference via Dynamic-Static Layer-Skipping for Robot Manipulationcited by 8
- 2025Revealing Perception and Generation Dynamics in LVLMs: Mitigating Hallucinations via Validated Dominance Correctioncited by 6
- 2026FBS: Modeling Native Parallel Reading inside a Transformercited by 6
- 2026Skip a Layer or Loop It? Learning Program-of-Layers in LLMscited by 6
- 2025From Compression to Expression: A Layerwise Analysis of In-Context Learningcited by 5
- 2025MorphServe: Efficient and Workload-Aware LLM Serving via Runtime Quantized Layer Swapping and KV Cache Resizingcited by 4
- 2026Jailbreaking Leaves a Trace: Understanding and Detecting Jailbreak Attacks from Internal Representations of Large Language Modelscited by 3
- 2025DeepInsert: Early Layer Bypass for Efficient and Performant Multimodal Understandingcited by 2
- 2025Dynamic Rebatching for Efficient Early-Exit Inference with DREXcited by 2
- 2026Deeper is Not Always Better: Mitigating the Alignment Tax via Confident Layer Decodingcited by 2
12 more
- 2025Skip-It? Theoretical Conditions for Layer Skipping in Vision-Language Modelscited by 1
- 2026MACRO: Markov Chain Routing of Transformer Layerscited by 1
- 2026Programs-of-Layers in LLMs through the Lens of Cortical Areascited by 1
- 2025Direct Multi-Token Decodingcited by 0
- 2025LiteStage: Latency-aware Layer Skipping for Multi-stage Reasoningcited by 0
- 2026BUDDY: BUdget-Driven DYnamic Depth Routing for Adaptive Large Language Model Inferencecited by 0
- 2026End-to-End Dynamic Sparsity for Resource-Adaptive LLM Inferencecited by 0
- 2026CausalGate: Causal Importance Distillation for Transformer Module Pruningcited by 0
- 2026Do Dynamic Routers Need Memory? HeRo: History-Aware Routing for Efficient LLM Inferencecited by 0
- 2026Theoretical Guarantees for One-Shot Magnitude Pruning and Compute-Adaptive Early Exitcited by 0
- 2026When Less Compute Is More: Adaptive Early Exit Improves Pretrained Outlier Detectioncited by 0
- 2026vSkipper: Translating Dynamic Layer Skipping into LLM Serving Gainscited by 0
- 2026vSkipper: Translating Dynamic Layer Skipping into LLM Serving Gains29 Sep 2026
- 2026When Less Compute Is More: Adaptive Early Exit Improves Pretrained Outlier Detection26 Sep 2026
- 2026Programs-of-Layers in LLMs through the Lens of Cortical Areas25 Sep 2026
- 2026Theoretical Guarantees for One-Shot Magnitude Pruning and Compute-Adaptive Early Exit11 Sep 2026
- 2026Do Dynamic Routers Need Memory? HeRo: History-Aware Routing for Efficient LLM Inference8 Sep 2026
- 2026MACRO: Markov Chain Routing of Transformer Layers6 Aug 2026
- 2026CausalGate: Causal Importance Distillation for Transformer Module Pruning21 Jul 2026
- 2026End-to-End Dynamic Sparsity for Resource-Adaptive LLM Inference26 Jun 2026
- 2026Deeper is Not Always Better: Mitigating the Alignment Tax via Confident Layer Decoding20 Jun 2026
- 2026BUDDY: BUdget-Driven DYnamic Depth Routing for Adaptive Large Language Model Inference8 Jun 2026
- 2026Skip a Layer or Loop It? Learning Program-of-Layers in LLMs4 Jun 2026
- 2026DySL-VLA: Efficient Vision-Language-Action Model Inference via Dynamic-Static Layer-Skipping for Robot Manipulation26 Feb 2026
12 more
- 2026Jailbreaking Leaves a Trace: Understanding and Detecting Jailbreak Attacks from Internal Representations of Large Language Models12 Feb 2026
- 2026FBS: Modeling Native Parallel Reading inside a Transformer29 Jan 2026
- 2025Revealing Perception and Generation Dynamics in LVLMs: Mitigating Hallucinations via Validated Dominance Correction21 Dec 2025
- 2025Dynamic Rebatching for Efficient Early-Exit Inference with DREX17 Dec 2025
- 2025Think-at-Hard: Dynamic Looped Transformers for Improved Reasoning11 Nov 2025
- 2025LiteStage: Latency-aware Layer Skipping for Multi-stage Reasoning16 Oct 2025
- 2025Dr.LLM: Dynamic Layer Routing in LLMs14 Oct 2025
- 2025Direct Multi-Token Decoding13 Oct 2025
- 2025Skip-It? Theoretical Conditions for Layer Skipping in Vision-Language Models29 Sep 2025
- 2025MorphServe: Efficient and Workload-Aware LLM Serving via Runtime Quantized Layer Swapping and KV Cache Resizing24 May 2025
- 2025From Compression to Expression: A Layerwise Analysis of In-Context Learning22 May 2025
- 2025DeepInsert: Early Layer Bypass for Efficient and Performant Multimodal Understanding27 Apr 2025
- 2025MorphServe: Efficient and Workload-Aware LLM Serving via Runtime Quantized Layer Swapping and KV Cache Resizingcited by 4
- 2025Dynamic Rebatching for Efficient Early-Exit Inference with DREXcited by 2
- 2026Do Dynamic Routers Need Memory? HeRo: History-Aware Routing for Efficient LLM Inferencecited by 0
- 2026Theoretical Guarantees for One-Shot Magnitude Pruning and Compute-Adaptive Early Exitcited by 0
- 2026When Less Compute Is More: Adaptive Early Exit Improves Pretrained Outlier Detectioncited by 0
- 2026vSkipper: Translating Dynamic Layer Skipping into LLM Serving Gainscited by 0
- 2026vSkipper: Translating Dynamic Layer Skipping into LLM Serving Gains29 Sep 2026
- 2026When Less Compute Is More: Adaptive Early Exit Improves Pretrained Outlier Detection26 Sep 2026
- 2026Theoretical Guarantees for One-Shot Magnitude Pruning and Compute-Adaptive Early Exit11 Sep 2026
- 2026Do Dynamic Routers Need Memory? HeRo: History-Aware Routing for Efficient LLM Inference8 Sep 2026
- 2025Dynamic Rebatching for Efficient Early-Exit Inference with DREX17 Dec 2025
- 2025MorphServe: Efficient and Workload-Aware LLM Serving via Runtime Quantized Layer Swapping and KV Cache Resizing24 May 2025
- 2025Dr.LLM: Dynamic Layer Routing in LLMscited by 10
- 2026FBS: Modeling Native Parallel Reading inside a Transformercited by 6
- 2026Skip a Layer or Loop It? Learning Program-of-Layers in LLMscited by 6
- 2025DeepInsert: Early Layer Bypass for Efficient and Performant Multimodal Understandingcited by 2
- 2026MACRO: Markov Chain Routing of Transformer Layerscited by 1
- 2026Programs-of-Layers in LLMs through the Lens of Cortical Areascited by 1
- 2025Direct Multi-Token Decodingcited by 0
- 2026BUDDY: BUdget-Driven DYnamic Depth Routing for Adaptive Large Language Model Inferencecited by 0
- 2026End-to-End Dynamic Sparsity for Resource-Adaptive LLM Inferencecited by 0
- 2026CausalGate: Causal Importance Distillation for Transformer Module Pruningcited by 0
- 2026Programs-of-Layers in LLMs through the Lens of Cortical Areas25 Sep 2026
- 2026MACRO: Markov Chain Routing of Transformer Layers6 Aug 2026
- 2026CausalGate: Causal Importance Distillation for Transformer Module Pruning21 Jul 2026
- 2026End-to-End Dynamic Sparsity for Resource-Adaptive LLM Inference26 Jun 2026
- 2026BUDDY: BUdget-Driven DYnamic Depth Routing for Adaptive Large Language Model Inference8 Jun 2026
- 2026Skip a Layer or Loop It? Learning Program-of-Layers in LLMs4 Jun 2026
- 2026FBS: Modeling Native Parallel Reading inside a Transformer29 Jan 2026
- 2025Dr.LLM: Dynamic Layer Routing in LLMs14 Oct 2025
- 2025Direct Multi-Token Decoding13 Oct 2025
- 2025DeepInsert: Early Layer Bypass for Efficient and Performant Multimodal Understanding27 Apr 2025