atomic - _mm_mwait 是如何工作的？

Question

如何_mm_mwait从pmmintrin.h工作？（我的意思不是它的 asm，而是行动以及如何在 NUMA 系统中采取这种行动。store监控很容易在基于总线的 SMP 系统上实现，并具有总线侦听功能。）

什么处理器实现它？

它用于某些自旋锁吗？

Answer 1

Every time a CPU on a multicore chip tries to write a specific memory address, all other CPUs, which have this particular memory address in their caches, have to be notified of that change. This notification could be used to implement the wakeup from MWAIT on modern CPUs independent of them having a single or separate memory busses.

What processors does implement it?

MWAIT is part of SSE3.

Is it used in some spinlocks?

This is contrary to the definition of a spinlock - the CPU is not busy.