You're right that pure spinlocks are usually a bad approach in usermode. Most implementations use a hybrid approach, where you spin for a short while, on the as

You're right that pure spinlocks are usually a bad approach in usermode. Most implementations use a hybrid approach, where you spin for a short while, on the assumption that another core holds the lock for only a short while, before you switch to blocking the thread. You might want to read https://webkit.org/blog/6161/locking-in-webkit/ https://webkit.org/blog/6161/locking-in-webkit/ about how Chrome implements high performance locks.