c – 虚假共享和128字节对齐/填充

/// An attribute that will cause a variable or field to be aligned so that
/// it doesn't have false sharing with anything at a smaller memory address.
#define FOLLY_ALIGN_TO_AVOID_FALSE_SHARING __attribute__((__aligned__(128)))

AFAIK,现代CPU上的缓存块是64字节长,实际上,我发现的所有资源,包括来自英特尔的this article,都谈到64字节的对齐和填充,以帮助解决虚假共享.

不过,Facebook的人员在需要的时候会将其成员调整为128字节.然后我发现刚刚在FOLLY_ALIGN_TO_AVOID_FALSE_SHARING的定义上面的解释的开始：

enum {
    /// Memory locations on the same cache line are subject to false
    /// sharing,which is very bad for performance.  Microbenchmarks
    /// indicate that pairs of cache lines also see interference under
    /// heavy use of atomic operations (observed for atomic increment on
    /// Sandy Bridge).  See FOLLY_ALIGN_TO_AVOID_FALSE_SHARING
    kFalseSharingRange = 128
};

虽然它给了我更多的细节,我仍然觉得我需要一些见解.我很好奇连续缓存行的同步,或者任何RMW操作在大量使用原子操作时可能会相互干扰.
有人可以告诉我如何才能发生这种情况吗？