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arXiv 2602.02632cs.LGcs.AI
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小型语言模型在FABRIC上的预训练性能:一项实证研究

Performance of Small Language Model Pretraining on FABRIC: An Empirical Study

The University of Missouri(密苏里大学)

Praveen Rao

AI总结:

本文研究小型语言模型在FABRIC实验平台上的预训练性能,探讨数据并行、操作符并行及流水线并行等技术对预训练效果的影响,发现Alpa在地理分布GPU上表现最佳。

摘要:

大型语言模型(LLMs)需要庞大的计算资源来在大规模数据集上预训练。当可用数据集有限时,较小的LLM是更合适的选择,通过遵循LLM的扩展规律在用户指定的数据集上进行预训练。使用预训练模型,可以生成原始数据的向量嵌入,并通过向量数据库存储,以支持现代AI应用和语义搜索。本文研究了小型LLM在实验平台(使用商用GPU)上的预训练性能,考虑了数据并行、操作符并行及操作符/流水线并行及其组合。我们建立了具有同构和异构GPU硬件的不同GPU集群。此外,我们研究了网络延迟对预训练性能的影响,特别是当GPU地理分布时。我们使用GPT-2中型和大型模型,并通过开源包Alpa和Ray进行预训练。我们发现,Alpa的执行计划在地理分布的GPU上表现最佳,尤其是当网络延迟在十毫秒级别时。基于实验获得的见解,我们提出了一种系统的方法,以选择合适的预训练技术,以实现高性能/低执行时间以及减少GPU数量。

英文摘要:

Large language models (LLMs) require enormous computing power to pretrain on massive datasets. When limited datasets are available, smaller-sized LLMs are better choice to pretrain (on user-specified datasets) by following the scaling laws of LLMs. Using pretrained models, vector embeddings can be generated for raw data and stored using vector databases to support modern AI applications and semantic search. In this work, we investigate the performance of pretraining techniques for smaller-sized LLMs on an experimental testbed (with commodity GPUs) available to academic users at no charge. We consider data parallelism, intra-operator parallelism, and inter-operator/pipeline parallelism, and their combinations for pretraining. We set up different GPU clusters with homogeneous and heterogeneous GPU hardware. Furthermore, we investigate the impact of network latency on pretraining performance especially when GPUs are geographically distributed. We used GPT-2 medium and large models and pretrained them using open-source packages, namely, Alpa and Ray. We observed that Alpa's execution plans that collectively optimized intra-operator and inter-operator/pipeline parallelism consistently performed the best when GPUs were geographically distributed. This was especially true when the network latencies were in 10's of milliseconds. Based on the insights gained from the experiments, we propose a systematic approach for selecting the appropriate pretraining technique to achieve high training performance/lower execution time as well as to reduce the number of GPUs used.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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