[extension]

Java probably outperforms JRuby primarily because the JVM was designed and tuned to run Java.

But in any case, if Twitter's architecture is truly scalable then any intrinsic slowness of the language shouldn't be a big problem, because they can just toss more hardware in to compensate. What is a problem is a buggy VM that leaks memory. To run thousands of instances in a heavily instrumented way, the VM must be stable and predictable.

[thebluesky]

Statically vs dynamically typed peformance difference is clear for virtually any static or dynamic language you care to name, it has nothing to do with the jvm being "tuned" for a language: http://shootout.alioth.debian.org/

[igouy]

>> peformance difference is clear for virtually any static or dynamic language you care to name <<

JavaScript

http://shootout.alioth.debian.org/u64/which-programs-are-fas...

[justincormack]

Only when they removed LuaJIT from the shootout, it is dynamic and fast (it was around where Java is in the benchmarks).

[nwienert]

How does that explain Julia[0]/Node.js? Both within 1-2x speed of C, I think static has less to do with it than you think.

[0] http://julialang.org/