Re:JVM Anatomy Quarks
by xxs on Friday January 31, 2020 @06:48PM
(#22207198)
Briefly:
- the lock has write a CAS on the =fast= read path, causing coherency traffic and a contention point between the readers. That's it the readers don't scale
- it's quite hard to use correctly, i.e. after read, determining the exclusive/write lock has to be acquired, the read lock has to be released 1st, the write lock acquired and the conditions that causes the grab to be rechecked
- Copy-On-Write should be a preferred solution for most cases, easy to understand and reason about. If not StampedLock is a better alternative.
- the lock has write a CAS on the =fast= read path, causing coherency traffic and a contention point between the readers. That's it the readers don't scale
- it's quite hard to use correctly, i.e. after read, determining the exclusive/write lock has to be acquired, the read lock has to be released 1st, the write lock acquired and the conditions that causes the grab to be rechecked
- Copy-On-Write should be a preferred solution for most cases, easy to understand and reason about. If not StampedLock is a better alternative.