alt Hacker NewsThis is true even at the CPU cache level so it's probably going to trickle down all the way.
For example Jon G gave a talk at Jane Street about how he had a mysterious performance bug that was later attributed to cores fighting over the same cache line
False sharing is pretty well known isn't it? I learned about it at university. It's the whole reason why the Linux "dwarves" tools were written, so you can check struct field alignment / grouping against cache line size and make sure you don't accidentally have two adjacent fields used by different cores.