[jordanthoms]

Copy-on-write fork is much faster than copying everything, but there is still some overhead setting up the copy-on-write state and dealing with the first writes afterwards, I think in cases where you have large amounts of memory vfork can still be useful.

[rab_oof]

The point isn't to prematurely optimize for edge-cases, but to tackle real, "hair-on-fire" performance bottlenecks head-on. If that means asking large-scale users to run profiling and getting stats of what's using tons of memory, slowing things down, duplicating work or wasting IOPS, go for it. If it's a dubious return/ effort at the expense of complexity, it might not be worth the investment.

For example, 'FooBarWidget @ Passenger 5 "Raptor" is a well-crafted, thoughtful achievement in terms of app servers.

2.2 Symbol GC also sounds great. I'm just not convinced there is enough innovation to make Ruby an order-of-magnitude faster, use less memory / return memory back to the system.