> I don't think it's worth doing this for low-level and highly
> artificial benchmarks like the ones run by pybench.

Well, it can help to know which opcodes are executed when running a
particular bunch of sub-tests :)

> If at all, then opcode statistics should be an optional feature
> enabled by a command line switch. I'd then create new methods
> bench.start_opcode_stats(), bench.stop_opcode_stats() and
> bench.get_opcode_stats().
> 
> Also note that this line will result in wrong results:
> 
> +            if opstats:
> +                opstats = [new - old
> +                    for new, old in zip(sys.getdxp(), opstats)]

You are right, my assumption was simply that the error would be in the
noise.