I don't know much about GitLab's code, but in my experience, language execution speed is one of the very last things you look for when optimizing the performanc

I don't know much about GitLab's code, but in my experience, language execution speed is one of the very last things you look for when optimizing the performance of a web application. The odds are overwhelmingly higher that the problem exists at the database, redis, API interaction, e-mailing, or 1,000 other things before rewriting in a faster language would be advantageous. Even then, it's often more cost effective to throw more servers at the problem. Web and worker servers typically scale horizontally effectively.