GPU621/Analyzing False Sharing

Preface

In multicore concurrent programming, if we compare the contention of mutually exclusive locks to "performance killers", then pseudo-sharing is the equivalent of "performance assassins". The difference between a "killer" and an "assassin" is that the killer is visible and we can choose to fight, run, detour, and beg for mercy when we encounter the killer, but the "assassin" is different. The "assassin" is always hiding in the shadows, waiting for an opportunity to give you a fatal blow, which is impossible to prevent. In our concurrent programming, when we encounter lock contention that affects concurrency performance, we can take various measures (such as shortening the critical area, atomic operations, etc.) to improve the performance of the program, but pseudo-sharing is something that we cannot see from the code we write, so we cannot find the problem and cannot solve it. This leads to pseudo-sharing in the "dark", which is a serious drag on concurrency performance, but we can't do anything about it.