That's great! Let the compiler figure out the optimal data layout then! Of course the architecture is relevant. But does everybody need to consider L2 and L3 sizes all the time? Optimizing this is for machines, with very rare exceptions. Expecting every programmer to do optimal data placement by hand is similar to expecting every programmer to call malloc and free in the right order and the correct number of times. And we know how reliable that turned out.
The compiler cannot know the _purpose_ of your program, and thus cannot "figure out the optimal data layout". It's metaphysically not possible, let alone technically.
Not everybody needs to worry about L2 or L3 most of the time, but if you are using a systems-level programming language where it might be of a concern to you at some point, it's extremely useful to be able to have that control.
> expecting every programmer to call malloc and free in the right order
The point of custom allocators is to not need to do the `malloc`/`free` style of memory allocation, and thus reduce the problems which that causes. And even if you do still need that style, Odin and many other languages offer features such as `defer` or even the memory tracking allocator to help you find the problems. Just like what was said in the article.
I am reluctant to believe compiler optimisations can do everything. Kind of reminds me of the time when people thought auto parallelisation would be a plausible thing. It never really happened, at least not in a predictably efficient way.
> That's great! Let the compiler figure out the optimal data layout then!
GHC, which is without a doubt the smartest compiler you can get your grubby mitts on, is still an extremely stupid git that can't be trusted to do basic optimizations. Which is exactly why it exposes so many special intrinsic functions. The "sufficiently smart compiler" myth was thoroughly discounted over 20 years ago.
> Let the compiler figure out the optimal data layout then!
Unfortunately, that's not possible. The optimal data layout depends on the order that data is accessed, which isn't knowable without knowing all possible ways the program could execute on all possible inputs.
