I don't recall exactly, but from what I remember, there were other benefits to the spin-lock approach. Don't we use some characteristics of this lock to properly shut down the system?
D. On Mon, Aug 31, 2015 at 5:24 AM, Vladimir Ozerov <voze...@gridgain.com> wrote: > Igniters, > > We have two pretty strange constructs: GridSpinReadWriteLock and base on it > GridSpinBusyLock. > As I understand it was an effort to create more performant RWLock than > ReentrantReadWriteLock > for cases when wrtie locks are very unlikely. > > As busy lock concept is also used in some sensitive places of "platforms" > module, I measured performance of read lock-unlock cycles for both > ReentrantReadWriteLock > and GridSpinReadWriteLock using JMH. > > Our implementation doesn't offer any perform benefits comparing to > ReentrantReadWriteLock, their performance are almost equal. This makes > sense, because essentailly both locks just CASes on a shared variable to > obtain the read lock. Looks like we can safely remove these "spinners" and > use ReentrantReadWriteLock instead. > > More serious perfomance gain can be achieved if we stripe the lock (e.g. > like it is done in LongAdder) thus decreasing contention on shared > variables. Quick experiments shown 5x throughput increase for read > lock-unlock cycles when lock is striped. > > Thoughts? > > Vladimir. >
