Christian Kellner
Senior Software Engineer at Apple
San Francisco, California, United States
Summary
🤩
Rockstar🎓
Top SchoolChristian Kellner is a Senior Software Engineer with 22 years of experience, currently at Apple in San Francisco, who blends low-level systems expertise (C, C++, Objective-C) with modern tooling in Swift and Python. He has a strong open-source track record across critical Linux and GNOME projects—improving Flatpak/GameMode integration, firmware update tooling (fwupd), and gnome-shell device authorization—which demonstrates deep knowledge of sandboxing, device firmware, and desktop integration. His career includes senior engineering and principal roles at Red Hat and long-term maintainership in GNOME, reflecting both technical leadership and sustained upstream contributions. Trained as a computational neuroscientist with an MA combining philosophy, CS and psychology, he brings a researcher's rigor to production engineering and testable, maintainable design. Notable but less obvious: he has repeatedly improved cross-platform build and testing infrastructure (mozilla/dxr, clBLAS), showing a knack for making complex native codebases reliably build and test across environments.
22 years of coding experience
17 years of employment as a software developer
Ludwig Maximilian University of MunichM.A., Philosophy, Computer Science & Psychology, With distinction, M.A., Philosophy, Computer Science & Psychology, With distinction at Universität Passau
English, German
Stackoverflow
1reputation
0reached
0answers
0questions
Github Skills (50)
opencl10
filesystem10
container10
javascript10
testing10
firmware10
thunderbolt10
linux10
bash10
flatpak10
c1110
blas10
file-operations10
dbus10
inotify10
Programming languages (22)
Github contributions (5)
FeralInteractive/gamemode
Jun 2018 - Oct 2019
Optimise Linux system performance on demand
Role in this project:
Backend Developer
Backend DeveloperContributions:47 commits, 13 PRs, 31 comments in 1 year 3 months
Contributions summary:Christian's contributions primarily focus on improving the performance and stability of the `gamemode` project, which is designed to optimize Linux system performance for gaming. They refactored the code to load versioned libraries, ensuring null termination in strings and eliminating old-style function definitions. The user also addressed memory leaks and optimized code through the use of defines and the implementation of auto-closing helpers.
on-demandoptimisevideogameslinuxdemand
clMathLibraries/clBLAS
Nov 2013 - Jun 2014
a software library containing BLAS functions written in OpenCL
Role in this project:Backend Developer
Backend DeveloperContributions:11 commits in 7 months
Contributions summary:Christian primarily focused on improving the `clblas` library's functionality and cross-platform compatibility, particularly for macOS. Their contributions included implementing nanosecond resolution timers, making Google Test work on OS X by linking against the Accelerate framework and using cblas functions, and fixing kernel cache issues. The user also addressed several build-related problems related to program options and corrected bugs in the BLAS functions.
cudalibrary-softwaregpublasopencl
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