@GenerateMicroBenchmark
@Group("Stamped")
@GroupThreads(1)
public long stWrites() {
long stamp;
long newValue;
stamp = stampedLock.readLock();
try {
BlackHole.consumeCPU(consumedCPU);
long currentValue = stampedAdder;
newValue = currentValue + 1;
long writeStamp = stampedLock.tryConvertToWriteLock(stamp);
if (writeStamp != 0L) {
stamp = writeStamp;
stampedAdder = newValue;
} else {
stampedLock.unlockRead(stamp);
stamp = stampedLock.writeLock();
BlackHole.consumeCPU(consumedCPU);
currentValue = stampedAdder;
newValue = currentValue + 1;
stampedAdder = newValue;
}
} finally {
stampedLock.unlock(stamp);
}
BlackHole.consumeCPU(consumedCPU);
return newValue;
}
@Override
public void increment() {
long stamp = stampedLock.writeLock(); // blocking lock, returns a stamp
try {
counter++;
} finally {
stampedLock.unlockWrite(stamp); // release the lock in the same block
}
}
@Override
public long getResult() {
long stamp = stampedLock.tryOptimisticRead(); // non blocking
long result = counter;
if (!stampedLock.validate(stamp)) {
// if a write occurred, try again with a read lock
stamp = stampedLock.readLock();
try {
return counter;
} finally {
stampedLock.unlockRead(stamp);
}
}
return result;
}
@GenerateMicroBenchmark
@Group("Stamped")
@GroupThreads(1)
public long stReads() {
long stamp;
long currentValue;
stamp = stampedLock.tryOptimisticRead();
BlackHole.consumeCPU(consumedCPU);
currentValue = stampedAdder;
if (!stampedLock.validate(stamp)) {
stamp = stampedLock.readLock();
try {
BlackHole.consumeCPU(consumedCPU);
currentValue = stampedAdder;
} finally {
stampedLock.unlockRead(stamp);
}
}
return currentValue;
}