I am thinking of a simple sum operation, which entails iterating through a set of integers and calling add for each. But the add operation could be implemented using complex stuff for handling BigInts, etc., so there could be a lot of nesting of so-called "contracts".

What I'm wondering is if there are any examples of how to model transactions down to the computer architecture's instruction level, the ISA (instruction set architecture), and how this could be implemented without a noticeable performance impact.

https://blockgeeks.com/guides/ethereum-gas-step-by-step-guide/

I'm also wondering if, in order to manage this as a performance problem, if any aggregation of blocks is performed. This would decrease the amount of blocks created.