> You can do it all with library functions that just take regular int* (and so on).

It's not just about atomics, but you might still find Hans Boehm's 2005 paper "Threads Cannot Be Implemented As a Library" [0] interesting. It describes (among other things) correctness and performance issues that can arise if the compiler and/or language don't know about thread/atomic semantics.

[0]: https://web.stanford.edu/class/archive/cs/cs240/cs240.1236/o...

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Joker_vD 3 hours ago | parent [-]

Yeah, it's all fun and games until you realize that you compiler may invent writes in order to eliminate a branch. Which is rather nonsensical, when you stop to think about it — surely an additional store to global can't be faster than a mispredicted branch?

	▲	homosapien97 2 hours ago \| parent \| next [-]
		Branch mispredictions on deep machines can be devastating, whereas a store can hit in your L1. Storing can definitely be faster than a mispredicted branch if you think you'll hit in your L1/L2
	▲	adgjlsfhk1 2 hours ago \| parent \| prev [-]
		store to a global is typically 0 cycles (although subsequent reads may be slowed down)