Jun 2018 – Sep 2020 · 2 yrs 3 mos · San Francisco Bay Area

Apr 2017 – Present · 9 yrs 1 mo

• Course taken:
• CS231n: Convolutional Neural Networks for Visual Recognition
• CS234: Reinforcement Learning
• CS221: Artificial Intelligence: Principles and Techniques
• CS224n: Natural Language Processing with Deep Learning
• CS161: Design and Analysis of Algorithms

Jul 2016 – Jun 2018 · 1 yr 11 mos

• Optimizing the software stack to bring down the time for people to get a ride.

Oct 2013 – Jul 2016 · 2 yrs 9 mos · San Francisco Bay Area

• As a core member of the Edge team, I lead the development of CloudFlare's caching system and logging system. I'm in charge of improving and maintaining CloudFlare's own version of Nginx web server. I'm also responsible for CloudFlare's content optimizations feature and email protection feature.
• Systems engineering
• Design and Implement CloudFlare's HTTP/2 + SPDY support, and the work is now fully open-sourced
• Finding hot spots of the production system using Systemtap, Flame Graph and successfully removed the bottlenecks.
• In charge of the design of CloudFlare's logging system, designed the format of the access log and created a Lua library to enable Nginx to log remotely. And also created very fast a Lua serialization library to serialize data to transfer on wire. Compared to JSON encoding, this library is 20X faster.
• Open source projects
• Authored an open source project: https://github.com/cloudflare/lua-resty-logger-socket, a remote logging library of OpenResty which allows Nginx web server to send data to remote logging server. This library is used by a lot of companies including CloudFlare.
• Authored an open source project: https://github.com/cloudflare/lua-resty-cookie, a library allows manipulating HTTP cookies (adding new cookies or removing current cookies) using Lua code in Nginx.
• Authored an open source project: https://github.com/calio/lua-capnproto, a Lua implementation of the data serialization project Cap'n Proto.
• Authored an open source project: https://github.com/calio/luaflow, a tool which scans Lua source code and draws call graphs based on the abstract syntax tree of the source file.

Jul 2011 – Sep 2013 · 2 yrs 2 mos · Beijing City, China

• As a project manager, lead the development of Lucid, a data abstraction layer. I'm responsible for the designing, development of this project. Technologies used are C and SQLite.
• Participate in a data visualization analysis product. Built a spider on top of Gearman job server. This project is mainly written in Python and PHP.
• Performance optimization for an image generation service. Rewrite this
• service using OpenResty and get a 100% performance improvement.
• As a project manager, lead the development of an asynchronous report system. I'm responsible
• for requirement engineering, system design, software design and communicating with other teams.

Mar 2010 – Jun 2011 · 1 yr 3 mos · Beijing

• Worked on OpenResty open source project.
• Rebuilt a data analysis product using Openresty.
• Wrote 3 Nginx modules (ngx_form_input, ngx_iconv, ngx_beanstalkd) for the OpenResty project.
• Wrote a Lua library to do in-memory relational algebra computations. This Lua library supports in-memory SQL operations like “select”, “group by”, “order by”, “where”, etc.
• Rebuilt a data analysis service using OpenResty. Wrote hundreds of
• web APIs. Those APIs query the Lua library that I have done to perform in-memory SQL operations.