cs.CLMay 19, 2025

EffiBench-X: A Multi-Language Benchmark for Measuring Efficiency of LLM-Generated Code

Authors: Yuhao Qing, Boyu Zhu, Mingzhe Du, Zhijiang Guo, Terry Yue Zhuo, Qianru Zhang, Jie M. Zhang, Heming Cui, 

Organizations: HKU · UCL · NTU · NUS · 

Abstract

Existing code generation benchmarks primarily evaluate functional correctness, with limited focus on code efficiency and often restricted to a single language like Python. To address this gap, we introduce EffiBench-X, the first multi-language benchmark designed to measure the efficiency of LLM-generated code. EffiBench-X supports Python, C++, Java, JavaScript, Ruby, and Golang. It comprises competitive programming tasks with human-expert solutions as efficiency baselines. Evaluating state-of-the-art LLMs on EffiBench-X reveals that while models generate functionally correct code, they consistently underperform human experts in efficiency. Even the most efficient LLM-generated solutions (Qwen3-32B) achieve only around 62% of human efficiency on average, with significant language-specific variations. LLMs show better efficiency in Python, Ruby, and JavaScript than in Java, C++, and Golang. For instance, DeepSeek-R1's Python code is significantly more efficient than its Java code. These results highlight the critical need for research into LLM optimization techniques to improve code efficiency across diverse languages. The dataset and evaluation infrastructure are submitted and available at https://github.com/EffiBench/EffiBench-X.git and https://huggingface.co/datasets/EffiBench/effibench-x.

Figures & tables

Appendix figures & tables34 assets

Supplementary material from the paper’s appendix.

Appendix

Explore similar work

CardsList
  1. Multi-LCB: Extending LiveCodeBench to Multiple Programming Languages

    Jun 18, 2026Maria Ivanova, Pavel Zadorozhny, Rodion Levichev +5Code GenerationCode Generation Evaluation