The net performance of your system is only as fast as the slowest part.
So, you optimized your C IO loop and it's really fast when there is not much Python...but soon as you add any Python, you'll be bottlenecking in Python and all that fastness wont matter...eg if you do some ORM SQL or any other thing that's more complex than `return data`
It's also interesting to compare energy usage. Intel has RAPL which allows you to measure the joules of a certain program or processor. We should be focusing not just on performance but also on environmental runtime impact.
So, you optimized your C IO loop and it's really fast when there is not much Python...but soon as you add any Python, you'll be bottlenecking in Python and all that fastness wont matter...eg if you do some ORM SQL or any other thing that's more complex than `return data`