[eregon]

> Guilds would have a major performance problem: can't allocate objects without GIL.

Why not? It'd be possible to have TLABs, isn't it? But yes, GC would still be for all Guilds at once.

Racket places don't allow to share objects, only arrays of primitive types, which seems very restrictive. And Racket futures are even more restricted.

I'm not sure about Guilds since it's not there yet, but it already sounds closer to Ruby multithreading and more flexible to me from an usage point of view.

[jashmatthews]

TLABs are definitely possible but it's increasing the implementation complexity.

Places are deliberately shared-nothing to reduce the implementation complexity and provide a simple model to the user. Process oriented code can be easily ported.

Porting something like a Sidekiq based worker using ActiveRecord to work inside a Guild where all access to shared objects needs to be frozen would be a nightmare.

With Racket Places you can share more complex types but it needs to be done via FFI. It doesn't prevent you from implementing a sharable connection pool or anything.