Kurt Stephens

Nice to see your experiment.

Tagging is, of course, a trade-off between time and space. But unless you run real application, you can not make any useful statement. Therefore, I dare that your test benchmark is not very meaningful.

We have run similar tests with the Pypy tool chain and the Spy Smalltalk VM, and found that the benefit (or not) of tagged pointers highly depends on the application that you are running and your actual needs. There is no definitive answer.

If you do not know Pypy, it is a tool chain to generate VMs from high-level code. Turning tagged pointers on/off ist just a simple switch on the command line, which makes it a very nice playground for experiments like yours.