Ruby allows optimisations in C for critical parts. In that sense I'd pin gitlab issues less on the language or framework, and more on a lack of resource to cover the weaker points.

I say that having seen a ton of PHP code base that is not stellar in itself, but has the more critical parts well optimized, going through external C libraries or DB hooks on parts that really warrant it.

I believe github onprem gets around the speed by using jruby? I’m sure that could be done with GitLab as well.

I just realized I've never actually seen on-prem Github. GitLab on the other side is everywhere, especially thanks to the Community Edition. I've never seen really big deployments, but for instances with 100-200 people on board there was never any problem (and DevOps guys sit right next to me, so I would probably hear something).

As for the hosted solutions, IMO both GitLab.com and Github.com are pretty slow. I've just recently started using non-premise solutions of both and Github slowness is really taking it's toll on my patience.

Guys, JIRA cloud is terribly slooow...

Sure, but that's an indictment of Atlassian products, not of Java for web.

For context: Ebay, Amazon and Google (Plus, Talk) are using Java for web. None of those are what I would consider slow.

If people were condemning Java for web as being slow, and Atlassian used Java and was slow, then you could reasonably assume that the reasons are correlated.

That is the case I'm making about Gitlab and RoR.

EDIT: you're mentioning Jira Cloud being slow, but we have the on-prem version and it's also very slow.

I have my doubts. From my experience, JRuby is generally slower. Source: used it in production at a billion dollar company, benchmarked it personally on individual items, contacted core devs when it was slower for advice.