You hardly need more than a simple script to just run a generic benchmark tool. But to measure performance of your code and figure out what needs to be tuned, I don't think LLMs are there, am I wrong? They can't understand the code they generated well enough to make small adjustments and improve the benchmark score. For a dev to do that on LLM generated code, it would have to understand the codebase as intended by the LLM at least.