Tim Felgentreff
Principal Researcher at Oracle Labs
Berlin, Germany
Summary
🤩
Rockstar🎓
Top SchoolTim Felgentreff is a Principal Researcher at Oracle Labs with 18 years of experience building high-performance language runtimes and dynamic VMs, and he leads the GraalPy team within the GraalVM project. He holds a PhD in IT Systems Engineering for work on object-constraint languages that enabled self-healing programs and novel UI/problem-solving techniques, and he has a strong JIT and VM research background from Hasso Plattner Institute. Tim combines deep systems-level expertise—memory-leak fixes, compilation improvements and shared-context stability for GraalVM—with hands-on contributions across notable open-source projects like Graal, GraalPython, Sinatra and the Ruby spec suite. His early work on Rails-based systems and game-engine mechanics demonstrates a practical breadth from web backends to low-level VM internals. Based in Berlin, he mentors students and engineers, bridging academic research with production-grade engineering in language implementation and runtime performance. An understated thread through his career is modernizing legacy systems—whether refactoring ChiliProject or evolving language parsers—so they remain extensible and robust.
18 years of coding experience
1 year of employment as a software developer
Doctor rerum naturalium (Dr. rer. nat.) IT Systems Engineering, Doctor rerum naturalium (Dr. rer. nat.) IT Systems Engineering at University of Potsdam
German, English, French, Chinese
Github Skills (54)
editors10
parser10
c-language10
strings10
game-engine10
graalvm10
python10
game-dev10
testing10
text-manipulation10
data-manipulation10
memory-management10
rails10
capi10
c1110
Programming languages (23)
Github contributions (5)
topazproject/topaz
Jun 2012 - Apr 2017
A high performance ruby, written in RPython
Role in this project:
Back-end Developer
Back-end DeveloperContributions:1042 commits, 14 PRs, 52 pushes in 4 years 10 months
Contributions summary:Tim's commits primarily focused on adding and improving the functionality of the Topaz Ruby implementation. This involved implementing new methods for the `String` and `Array` classes, such as `ljust`, `rstrip`, `each_line`, and `byteslice`. Further contributions included implementing methods like `String#succ`, `Array#flatten` and features like keyword arguments in methods, as well as enhancements to the parser to support these features. The work demonstrates a focus on expanding the Ruby standard library and improving compatibility.
performancepythonrubyhigh-performance
Wargus/stratagus
Apr 2015 - Jan 2023
The Stratagus strategy game engine
Role in this project:Back-end Developer
Back-end DeveloperContributions:13 releases, 15 reviews, 152 commits in 7 years 10 months
Contributions summary:Tim primarily contributed to the Stratagus strategy game engine by modifying and extending its core functionalities. Their work included adjusting the maximum map size, allowing more flexible unit animations, and enhancing the building rules via Lua callbacks. Furthermore, the user implemented movement features, subtile movement speeds, and refined code related to game speed and build-related operations. These changes suggest an active role in improving the game engine's mechanics.
gamestrategygame-developmentgame-enginestrategy-game
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