[stcredzero]

So Ruby objects occupy 40 bytes each, inside pages on the eden heap.

That's pretty huge. That's several times larger than some other dynamic languages -- languages that have essentially the same features as Ruby.

[phamilton]

Not really. Python primitives are smaller (24 bytes). Python strings are 37 + 1 byte per character. Python objects are 72 bytes. Python classes are 104 bytes. (Got these numbers playing around with sys.getsizeof in the python console.)

Primitives are a bit bigger in ruby, but they aren't really primitives anyway (everything is an object).

[stcredzero]

Python is another offender!

[phamilton]

What languages are you referring to than? Perl and PHP are really the only others that are sort of in the same class as Ruby and Python.

[stcredzero]

Smalltalk, for one.

[rurban]

Perl objects are even bigger and need one indirection per access. A perl head is 32 bytes plus 48 byte body, ie. 80byte on 64bit systems.

For my perl rewrite p2 I need one single word per object on the stack. Common Lisps usually needs two words, the class pointer and the tagged value.

I really liked the visualization of the various GC's btw. Excellent work!

[riffraff]

I have no idea of the size in other language implementations, but notice 40 bytes is on x86-64, on 32 bit it's either 20 or 24.

[joevandyk]

this is why running large ruby apps on 64 bit OSs can take up a lot more memory than 32 bit.

[riffraff]

isn't that true of most platforms? I know the JVM has compressed OOPS to limit this issue, but I am not aware of similar things elsewhere.