[Jormundir]

Because performance can largely be displaced to outside the app code itself. Things like cacheing, load balancers and large amounts of front-ends make the optimization differences of these platforms largely irrelevant for large projects, and especially large companies that don't mind throwing more money to increase the amount of front-end servers.

For smaller projects, or for companies / people with tight budgets, these performance tests matter more, though the biggest wins still lie in cacheing and load balancing, not in platform efficiency. This can depend on the nature of the application though. Some have tons of cacheable content, some have tons of dynamic content.

[Sssnake]

>saving tens of millions of dollars is largely irrelevant

Why do people seriously say nonsense like this? Why do you think facebook spends so much money on hiphop/HHVM? Because yes, performance certainly does matter. Slow languages and slow frameworks cost tons of money.

[JTenerife]

Well, it's not irrelevant, but it's common practice. Of course bad practice. Seen it myself. Facebook and others might be able to choose the better approach but a lot of badly managed companies / projects choose the last resort solution to through out millions of dollars for hardware as they're incapable of fixing the problems properly. Those projects are politically screwed, so they often sell their solution to buy expensive hardware as success. Sounds ill, I know ...

[Jormundir]

Nice misquote. Put some numbers out.

The evolution of a project as I've seen it at large companies:

1. Build slow app in high level language, build out your infrastructure with cacheing and load balancing, CDNs, etc. 2. See what is slow / can be optimized in the current language. 3. Re-implement critical pieces in a lower level, more efficient language.

Facebook is building HHVM to eliminate step 3. You can have a bunch of people continuously re-implementing critical pieces, or you can have a smaller bunch of people make the higher level language more efficient once and have all your projects, current and future, benefit. And you also save money from the inefficient language.

I'd like to see the numbers on how much, say, using Ruby with all the optimizations - load balancers, cacheing, etc. will cost you over using Java - also with optimizations. I'm not convinced by a random person's statement that it is that huge of an impact, especially considering factors like finding programmers for optimized languages, productivity differences in programming in the different languages, etc.

[Sssnake]

Yeah, finding java programmers is super hard. Not like there's literally hundreds of times more of them than there are ruby programmers or anything. Facebooks is building HHVM because it is too late to do it right in the first place. If they started with reasonably performant language they'd have saved millions on servers, plus millions on developers writing HHVM. You are posting in a discussion about the very numbers you want. Go look at them.