https://github.com/protocolbuffers/protobuf/commit/50f9ac3ba...

On a sufficiently anemic CPU doing enough fast allocation you can get measurable improvements from that kind of thing, but for a superscalar CPU and a general purpose allocator I agree you'd be hard pressed.

Not sure that protobuf change is the same thing

But you might be right on your overall point: on my big x86 CPU, it doesn't matter, but it might matter on some tiny arm thingy