[celrod]

To tie Octavian.jl into this memory allocation discussion:

Octavian uses stack-allocated temporaries when "packing" left matrix ("A" in "A*B"). These temporaries can have tens of thousands of elements, so that's a non-trivial stack allocation (the memory is mutable to boot). No heap allocations or GC activity needed (just a GC.@preserve to mark its lifetime). If I understand correctly, this isn't something that'd be possible in Java?

To be fair, you can also just use preallocated global memory for your temporaries, since the maximum amount of memory needed is known ahead of time.