It is not only about absolute number of objects created, of course. It is also how long they kept and how often the are changing.
Immutability gives simplifies everything including incremental, parallel GC and hence reduces the pauses for GC.
This is the big idea behind Clojure and Datomic - immutability makes everything simple (less complex runtimes) and even more scalable (share nothing means no locks, mutexes, busy waiting) and in the case of Erlang - fault tolerant (strong process isolation - no threads with shared stack or any writable data).
What is funny - everything has been well-researched and right principles formulated by Erlang team decades ago, and the resulting product just works for telecoms.
The two fundamental principles they described are 1) Posix threads and fault tolerance does not match. 2) Imperative code and GC does not match. While Golang, Lua or PyPy are trying really hard to disprove the second principle, Java is an existential proof.
That's kind of a digression, but the Lua GC is pretty simple (which is good) and not so efficient. The LuaJIT GC has some interesting features but sadly Mike Pall did not complete all of his plans for it.
What makes LuaJIT so efficient regarding the GC is that you can allocate memory that is not managed by it (using the FFI). You have to if you need to use a lot of memory anyway, since depending on the architecture GCd memory can be limited to as little as 1 GB.
Immutability gives simplifies everything including incremental, parallel GC and hence reduces the pauses for GC.
This is the big idea behind Clojure and Datomic - immutability makes everything simple (less complex runtimes) and even more scalable (share nothing means no locks, mutexes, busy waiting) and in the case of Erlang - fault tolerant (strong process isolation - no threads with shared stack or any writable data).
What is funny - everything has been well-researched and right principles formulated by Erlang team decades ago, and the resulting product just works for telecoms.
The two fundamental principles they described are 1) Posix threads and fault tolerance does not match. 2) Imperative code and GC does not match. While Golang, Lua or PyPy are trying really hard to disprove the second principle, Java is an existential proof.