Heungsub Lee
- Contact
- [email protected]
- Web Sites
- subl.ee, github.com/sublee, linkedin.com/in/sublee
Interest
Software architectures, distributed systems, cost optimization, developer experience, and the open source culture.
Skills
- Programming Languages
- Go, Python, TypeScript, Bash
- Service Development
- Linux, AWS, K8s, Pulumi, React, ZeroMQ, NoSQL, Concurrent programming, Testing
- ML Engineering
- PyTorch, NVIDIA Nsight Systems, NCCL
Work Experience
- Software Engineer
- Global AI Platform, Sep 2023 – Present
- Focusing on making everyone utilize AI for their daily productivity. Developed and maintained the client and server of Gistty, a Chrome extension summarizing Amazon reviews.
- Software Engineering Manager
- NAVER, Aug 2020 – Jul 2023
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Supervised MLOps platforms by leading 25 software engineers to optimize the inference performance and productivity of HyperCLOVA, an LLM specializing in Korean culture.
Developed NSMLv2, a large-scale ML research platform in CLOVA. Designed its multitenant architecture based on economics to share GPU clusters for HPC among diverse organizations with complex desires while utilizing GPU resources efficiently.
- Software Engineer
- Kakao Brain, Dec 2018 – Aug 2020
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Developed and published a pipeline parallelism library named torchgpipe in open source.
Developed a serverless training framework and a distributed hyperparameter search platform for an AutoML service.
- Game Server Engineer
- NEXON, Mar 2011 – Dec 2018
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Developed cloud-based distributed MMORPG servers for Durango using pub/sub communication over the spatial grid system. Achieved up to 70k concurrent users per game world.
Developed online racing game servers and matchmaking for KartRider Dash and KartRider Coin Rush.
- Back-end Web Developer
- nPine, Dec 2008 – Feb 2011
- Developed web services selling stock images.
Open Source Experience
- torchgpipe, Feb 2019 – Apr 2020
- Implemented GPipe, a multi-GPU pipeline parallelism technique for training giant models, as a PyTorch library with optimization for CUDA, the autograd engine, and long skip connections. This project has become a part of PyTorch as Pipe APIs
- Hangulize, Oct 2010 – Present
- Invented a Hangul transcription algorithm and served as a web tool at zero cost. Many professional Korean translators use this tool to translate undocumented proper nouns.
- TrueSkill, Jan 2012 – Dec 2015
- Implemented TrueSkill™, the rating algorithm for Xbox Live, as a Python library. This project was introduced in PyData Berlin 2019.
- Contributions
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- For PyTorch, fixed potential GPU memory violation (#27371); deprecated inconsistent API (#21006, #25985); discussed a counterintuitive behavior of the autograd engine (#18568).
- For ZeroMQ, discussed a PUB socket crash (#2942).
- For Flask, fixed a bug to generate a URL with a subdomain (#108).
- For jQuery 1.4.3, fixed a bug on content negotiation in Ajax requests.
Publications
- B. Kim et al., “What changes can large-scale language models bring? Intensive study on HyperCLOVA: Billions-scale Korean generative pretrained Transformers,” arXiv:2109.04650, Sep 2021.
- C. Kim*, Heungsub Lee* et al., “torchgpipe: On-the-fly pipeline parallelism for training giant models,” arXiv:2004.09910, Apr 2020.
*Contributed equally
Public Speeches
- “NSML, the hyper-scale ML training platform,” KRnet, Jun 2022.
- “Remake of Hangulize,” Golang Korea Meetup, Aug 2018.
- “Profiling,” PyCon Korea, Aug 2015.
- “The server architecture of Durango,” NDC, 2014, 2016, and 2018.
Languages
- Korean — Native
- English — Conversant in reading and writing
Education
Computer Software, Kwangwoon University, 2008, Completed the first year only.