False sharing

In computer science, false sharing is a performance-degrading usage pattern that can arise in systems with distributed, coherent caches at the size of the smallest resource block managed by the caching mechanism. When a system participant attempts to periodically access data that is not being altered by another party, but that data shares a cache block with data that is being altered, the caching protocol may force the first participant to reload the whole cache block despite a lack of logical necessity.[1] The caching system is unaware of activity within this block and forces the first participant to bear the caching system overhead required by true shared access of a resource.

  1. ^ Patterson, David (2012). Computer organization and design: the hardware/software interface. Waltham, MA: Morgan Kaufmann. p. 537. ISBN 978-0-12-374750-1. OCLC 746618653.