Gregory Mierzwinski
Potton, Quebec, Canada
Summary
🤩
Rockstar🎓
Top SchoolGregory Mierzwinski is a performance-focused software engineer with a decade of experience building and maintaining test harnesses and CI-driven performance tooling at Mozilla, now helping lead a small engineering team. He has deep hands-on expertise in web and Android performance measurement—contributing key enhancements to the widely used Browsertime project and integrating visual metrics into Firefox for Android (Fenix) test workflows. Gregory combines research-grade analytical skills from an MS in biomedical imaging with practical DevOps and full-stack development chops, able to instrument, automate and analyze regressions end-to-end. He also teaches advanced programming courses at Bishop’s University and runs a small investment company, demonstrating an aptitude for explaining technical concepts and balancing diverse responsibilities. Based in Potton, Quebec, he contributes to open-source performance tooling while applying empirical approaches learned in academic imaging research to software performance problems.
10 years of coding experience
7 years of employment as a software developer
Master of Science - MS, Radiation Science and Biomedical Imaging - Research based, Master of Science - MS, Radiation Science and Biomedical Imaging - Research based at Université de SherbrookeBachelor of Science - BS, Computer Science, Bachelor of Science - BS, Computer Science at Bishop's University
English, French, Polish
Github Skills (15)
javascript10
docker10
firefox10
chrome10
performance-optimization10
python10
android10
dockers10
cicd10
cli10
automations9
automation9
video-processing9
testing8
mozilla7
Programming languages (13)
Github contributions (5)
sitespeedio/browsertime
Dec 2019 - Sep 2022
Measure and Optimize Web Performance
Role in this project:
Full-stack Developer
Full-stack DeveloperContributions:1 release, 23 reviews, 57 commits in 2 years 9 months
Contributions summary:Gregory primarily contributed to the Browsertime project by implementing and enhancing features related to performance measurement and optimization. This involved modifying the command-line interface (CLI) to add new options for Chrome and Firefox, integrating functionalities for Android power testing, and improving video recording capabilities. Furthermore, the user addressed issues related to gecko profile collection, and enhanced various code modules, like fixing linting errors and addressing merge conflicts.
safarifirefoxbrowserharjavascript
mozilla-mobile/fenix
Mar 2020 - Nov 2022
⚠️ Fenix (Firefox for Android) moved to a new repository. It is now developed and maintained as part of: https://github.com/mozilla-mobile/firefox-android
Role in this project:DevOps Engineer
DevOps EngineerContributions:37 reviews, 43 commits, 57 PRs in 2 years 8 months
Contributions summary:Gregory primarily focused on integrating and testing visual metrics within the Fenix (Firefox for Android) repository. They implemented and refined automated visual metric tests using browsertime and Docker, integrating them into a cron task and pull request testing processes. The user's work involved setting up dependencies, configuring testing environments, and debugging issues related to visual metric collection, including incorporating similarity metrics and modifying script logic. Their contributions included updates to the `run-visual-metrics.py` script and modifications to task graph definitions.
firefoxbrowserandroidfirefox-for-androidmozilla
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