total store order

x86-64's memory model: other cores see each core's stores in order and its loads in order, but a later load may get ahead of an earlier store.

x86-TSO (total store order) is the x86-64 model: each core's stores pass through a FIFO store buffer, all stores become visible in one global order, and the only reordering visible to other cores is a later load completing before an earlier store to a different address; locked instructions and mfence drain the buffer.