5.10 Parallelism and Memory Hierarchy: Cache Coherence
Given that a multicore multiprocessor means multiple processors on a single chip, these processors very likely share a common physical address space. Caching shared data introduces a new problem, because the view of memory held by two different processors is through their individual caches, which, without any additional precautions, could end up seeing two distinct values. Figure 5.40 illustrates the problem and shows how two different processors can have two different values for the same location.
This difficulty is generally referred to as the cache coherence problem.
节录自Computer Organization and Design
PH的教科书
这就计算机结构课程里的东西
我完全看不出跟这个议题的关连性在哪
有兴趣钻研的人还可以看
A Primer on Memory Consistency and Cache Coherence
https://course.ece.cmu.edu/~ece847c/S15/lib/exe/fetch.php?media=part2_2_sorin12.pdf