If a program reads a single byte in memory, the processor loads the whole cacheline that contains that byte into the L2 and L1 caches.
如果一个程序在存储中读到一个单独的字节，处理器就会释放包含字节的所有的缓存线到L2和L1缓存中。
2
If the data or instruction is not present in the cache, or if the cacheline is invalidated, the CPU updates its cache by reading the data from the main memory.
By separating the two elements of the structure into two different cache lines, modification of one cacheline does not cause another cacheline to be read in again from the memory.