Hi Kim,
On 06/29/2016 01:22 PM, Peter Levart wrote:
Transfering the whole list in one JNI invocation has the potential for
further optimizations on the Java side (like handling the whole popped
list privately without additional synchronization - if we ever find a
way for java.nio.Bits to wait for it reliably - or even enqueue-ing a
chunk of consecutive references destined for the same queue using a
single synchronized action on the queue, etc...)
Just to show what I mean, here's a simple optimization that doesn't use
a private pendingList of references shared among callers of
tryHandlePanding(true/false), but instead uses course-grained
synchronization and waiting for tryHandlePanding(false) callers while
ReferenceHandler is privately processing the whole list of pending
references:
http://cr.openjdk.java.net/~plevart/misc/PendingReferenceHandling/webrev.02/
This further improves benchmark results and it still passes the
DirectBufferAllocTest:
Original JDK 9:
Benchmark (refCount) Mode Cnt
Score Error Units
ReferenceEnqueueBench.dequeueReferences 100000 ss 100 38410.515
± 1011.769 us/op
Patched (by Kim):
Benchmark (refCount) Mode Cnt
Score Error Units
ReferenceEnqueueBench.dequeueReferences 100000 ss 100 42197.522
± 1161.451 us/op
Proposed (by Peter, webrev):
Benchmark (refCount) Mode Cnt
Score Error Units
ReferenceEnqueueBench.dequeueReferences 100000 ss 100 34134.977
± 1274.753 us/op
Proposed (by Peter, webrev.02):
Benchmark (refCount) Mode Cnt
Score Error Units
ReferenceEnqueueBench.dequeueReferences 100000 ss 100 27935.929
± 1128.678 us/op
Regards, Peter
