On Tue, 27 Jun 2023 13:57:31 GMT, Chen Liang <li...@openjdk.org> wrote:
>> This patch implements lazy initialization for VarHandle working on static
>> fields. It has a good initial call performance.
>>
>> We introduce a new internal API, `target()` to unpack a lazy VarHandle in VH
>> implementation methods. If called via MethodHandle, a barrier is added in
>> the MethodHandle instead.
>>
>> The new test ensures the correctness of Lazy VH for both direct and indirect
>> invocation; the performance of MethodHandle version of lazy VH is not yet
>> tested.
>>
>>
>> Benchmark Mode Cnt Score
>> Error Units
>> LazyStaticColdStart.methodHandleCreateEager ss 10 41.490 ±
>> 12.331 us/op
>> LazyStaticColdStart.methodHandleCreateLazy ss 10 21.810 ±
>> 16.964 us/op
>> LazyStaticColdStart.methodHandleInitializeCallEager ss 10 57.860 ±
>> 13.738 us/op
>> LazyStaticColdStart.methodHandleInitializeCallLazy ss 10 93.300 ±
>> 18.858 us/op
>> LazyStaticColdStart.varHandleCreateEager ss 10 39.860 ±
>> 9.362 us/op
>> LazyStaticColdStart.varHandleCreateLazy ss 10 17.630 ±
>> 1.111 us/op
>> LazyStaticColdStart.varHandleInitializeCallEager ss 10 123.170 ±
>> 62.468 us/op
>> LazyStaticColdStart.varHandleInitializeCallLazy ss 10 105.390 ±
>> 41.815 us/op
>
> Chen Liang has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Rollback VHG changes
src/java.base/share/classes/java/lang/invoke/LazyInitializingVarHandle.java
line 63:
> 61: }
> 62:
> 63: @ForceInline
Suggestion:
@Override
@ForceInline
src/java.base/share/classes/java/lang/invoke/VarHandle.java line 2210:
> 2208:
> 2209: /**
> 2210: * Computes a method handle that can be passed the {@linkplain
> #target() direct}
Suggestion:
* Computes a method handle that can be passed the {@linkplain #asDirect()
direct}
?
test/jdk/java/lang/invoke/VarHandles/LazyInitializingTest.java line 85:
> 83:
> 84: @Test
> 85: public void testInitializationOnVarHandleUse() {
I think we will need to expand this to also test operating on a MH to a VH, an
indirect VH, and on a MH to indirect VH. We could do this separately.
test/micro/org/openjdk/bench/java/lang/invoke/LazyStaticColdStart.java line 92:
> 90: });
> 91:
> 92: static {
Is this static block required?
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/13821#discussion_r1244336226
PR Review Comment: https://git.openjdk.org/jdk/pull/13821#discussion_r1244362027
PR Review Comment: https://git.openjdk.org/jdk/pull/13821#discussion_r1244367651
PR Review Comment: https://git.openjdk.org/jdk/pull/13821#discussion_r1244367889
