Lets say you have 8 independent counters and 4 CPUs. Each gets 4 slots in 4-cacheline = 256 byte storage. Counter0 gets slots 0, 64, 128, and 192. Counter1 gets

Lets say you have 8 independent counters and 4 CPUs. Each gets 4 slots in 4-cacheline = 256 byte storage. Counter0 gets slots 0, 64, 128, and 192. Counter1 gets slots 8, 72, 136, and 200. And so on. Then you map CPU0 to slot 0, CPU1 to slot 1, CPU2 to slot 2, and CPU3 to slot 3. Since we share the mapping between all counters. Any bump of any counter on CPU0 touches only cache line 0. So there isn't any false sharing. In practice, mapping CPU to slot isn't quite so easy. But you can get a pretty good mapping using the strategy in this post, or something like folly::AccessSpreader::cachedCurrent() [0]. In new kernels, I believe there is kernel support for getting this mapping, using the rseq library. The kernel will update the current CPU in a thread local on every context switch. [0] https://github.com/facebook/folly/blob/a590a0e559d0f1c7af442803b778e6c5d92ba569/folly/concurrency/CacheLocality.h#L267 https://github.com/facebook/folly/blob/a590a0e559d0f1c7af442...