Inference Efficiency & Long Context
Calibration-Free and Gradient-Free Predictors for Efficient Inference
Generated automatically from the limitations stated in 4 papers (EMNLP, ICML), listed under Evidence. It is not a paper, and it does not come from papers submitted to CSPaper.
The problem
Current efficiency mechanisms for large language models and long-context inference—such as dynamic quantization, layer skipping, and speculative routing—rely on offline calibration phases requiring gradient access and curated calibration datasets. Consequently, these acceleration techniques cannot be deployed in privacy-sensitive environments where data cannot be stored, nor on black-box model APIs where backpropagation is unavailable. Furthermore, because predictors are model-specific, serving heterogeneous or frequently updated models incurs repeated offline profiling overhead that impedes zero-shot deployment.
Why it matters
Enables privacy-preserving, plug-and-play acceleration of long-context models and proprietary inference APIs without offline dataset collection or gradient computation.
Ways to approach it
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- 1
Test-time forward-only profiling: Build dynamic pruning and quantization selectors driven solely by streaming activation statistics (e.g., kurtosis, attention entropy) without backpropagation, measuring throughput gains and perplexity degradation against gradient-calibrated baselines.
- 2
Proxy-model calibration transfer: Calibrate predictor heads on small, open-source proxy models and test zero-shot transferability to larger, black-box target models, measuring cross-architecture routing accuracy and downstream task retention.
- 3
Non-parametric logit calibration: Replace softmax probability scaling with rank-order statistics and uncertainty measures that require no offline dataset, measuring calibration error and decision correctness on long-context question answering.
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Why it might fail
If the decision boundaries required for effective dynamic inference are tightly coupled to second-order loss gradients that forward-only activation statistics fundamentally fail to capture without substantial accuracy loss.
Evidence
Each paper's own statement of the limitation, verbatim.
- GRASP: Replace Redundant Layers with Adaptive Singular Parameters for Efficient Model CompressionEMNLP 2025
Requires gradient access and a calibration dataset, so it cannot be applied in strictly black-box or privacy-sensitive settings
- Cache Me If You Must: Adaptive Key-Value Quantization for Large Language ModelsICML 2025
Predictors are model-specific and must be recalibrated per model with ~224 calibration sequences; the paper foregoes global fine-tuning and dynamic bit-widths, leaving potential gains unrealized.
- ShadowLLM: Predictor-based Contextual Sparsity for Large Language ModelsEMNLP 2024
Requires an offline calibration phase to compute gradients and train the predictor on a specific dataset.
- Model Cascading: Towards Jointly Improving Efficiency and Accuracy of NLP SystemsEMNLP 2022
Reliant on softmax probability calibration, which may not always perfectly correlate with predictive correctness.
Nearest existing work
- Self-calibration for Language Model Quantization and PruningNAACL 2025
- Training–Inference Consistent Segmented Execution for Long-Context LLMsICML 2026
- The Right Tool for the Job: Matching Model and Instance ComplexitiesACL 2020
- APT: Adaptive Pruning and Tuning Pretrained Language Models for Efficient Training and InferenceICML 2024
- APB: Accelerating Distributed Long-Context Inference by Passing Compressed Context Blocks across GPUsACL 2025
- Context-Aware Assistant Selection for Improved Inference Acceleration with Large Language ModelsEMNLP 2024
- You Only Prune Once: Designing Calibration-Free Model Compression With Policy LearningICLR 2025
- On the Impact of Calibration Data in Post-training Quantization and PruningACL 2024
- QuantSpec: Self-Speculative Decoding with Hierarchical Quantized KV CacheICML 2025
- Reasoning Models Can be Accurately Pruned Via Chain-of-Thought ReconstructionICLR 2026
- GradOT: Training-free Gradient-preserving Offsite-tuning for Large Language ModelsACL 2025
- RaBitQCache: Rotated Binary Quantization for KVCache in Long Context LLM InferenceICML 2026
- Black-Box Tuning for Language-Model-as-a-ServiceICML 2022
- Beware of Calibration Data for Pruning Large Language ModelsICLR 2025
- Pretraining Context Compressor for Large Language Models with Embedding-Based MemoryACL 2025