Saved in:
Bibliographic Details
Main Authors: Zai, Liu, Klampanos, Iraklis
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2601.05833
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866910182356811776
author Zai, Liu
Klampanos, Iraklis
author_facet Zai, Liu
Klampanos, Iraklis
contents Pretokenization is a crucial, sequential pass in Byte-level BPE tokenizers, yet little work has been done to optimize it for edge-side inference. Our proposed new implementation, Peek2, serves as a drop-in replacement for cl100k-like pretokenizers used in GPT-3, LLaMa-3, and Qwen-2.5. After breaking down and analyzing the logic of the original cl100k pretokenizer, we introduced a new pretokenization algorithm with linear time complexity and constant, trivial memory usage, suited for edge scenarios. Test results show that it increases microbenchmarking throughput by up to $ 2.48\times $ and delivers a $ 1.14\times $ improvement in overall throughput across the entire Byte-level BPE encoding process, depending on the dataset, while providing identical results as the baseline Regex-based tokenizer.
format Preprint
id arxiv_https___arxiv_org_abs_2601_05833
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Peek2: Regex-free Byte-level Byte-Pair Encoding Pretokenizer for LLM Inference on Edge Devices
Zai, Liu
Klampanos, Iraklis
Computation and Language
D.2.0; F.3.1
Pretokenization is a crucial, sequential pass in Byte-level BPE tokenizers, yet little work has been done to optimize it for edge-side inference. Our proposed new implementation, Peek2, serves as a drop-in replacement for cl100k-like pretokenizers used in GPT-3, LLaMa-3, and Qwen-2.5. After breaking down and analyzing the logic of the original cl100k pretokenizer, we introduced a new pretokenization algorithm with linear time complexity and constant, trivial memory usage, suited for edge scenarios. Test results show that it increases microbenchmarking throughput by up to $ 2.48\times $ and delivers a $ 1.14\times $ improvement in overall throughput across the entire Byte-level BPE encoding process, depending on the dataset, while providing identical results as the baseline Regex-based tokenizer.
title Peek2: Regex-free Byte-level Byte-Pair Encoding Pretokenizer for LLM Inference on Edge Devices
topic Computation and Language
D.2.0; F.3.1
url https://arxiv.org/abs/2601.05833