On Wed, 6 Nov 2024 17:28:08 GMT, jengebr <d...@openjdk.org> wrote:
>> src/java.base/share/classes/java/lang/PublicMethods.java line 108:
>>
>>> 106: Class<?>[] ptypes) {
>>> 107: // check for matching param types length, then name, then
>>> param type equality
>>> 108: return method.getParameterCount() == ptypes.length &&
>>
>> Length check is already present in `equals`. If you want this fast path, I
>> think moving arrays equals check first is better.
>
> I benchmarked variations on this and got some surprises. The noArg change
> was removed prior to any experiments, so this is strictly the `matches()`
> optimization.
>
> Base case (no PR):
>
> Benchmark Mode Cnt Score Error Units
> ClassGetMethod.getConcreteFiveArg avgt 6 94.586 ± 0.733 ns/op
> ClassGetMethod.getConcreteNoArg avgt 6 75.587 ± 11.300 ns/op
> ClassGetMethod.getIntfFiveArg avgt 6 215.794 ± 7.713 ns/op
> ClassGetMethod.getIntfNoArg avgt 6 200.418 ± 4.352 ns/op
> ClassGetMethod.getNoSuchMethod avgt 10 2207.928 ± 49.767 ns/op
> ClassGetMethod.getSuperFiveArg avgt 6 190.142 ± 1.995 ns/op
> ClassGetMethod.getSuperNoArg avgt 6 153.943 ± 7.491 ns/op
>
>
> With `Arrays.equals()`, then name:
>
> Benchmark Mode Cnt Score Error Units
> ClassGetMethod.getConcreteFiveArg avgt 6 82.949 ± 7.614 ns/op
> ClassGetMethod.getConcreteNoArg avgt 6 98.248 ± 11.482 ns/op
> ClassGetMethod.getIntfFiveArg avgt 6 204.604 ± 5.656 ns/op
> ClassGetMethod.getIntfNoArg avgt 6 225.582 ± 5.238 ns/op
> ClassGetMethod.getNoSuchMethod avgt 10 2216.038 ± 48.732 ns/op
> ClassGetMethod.getSuperFiveArg avgt 6 172.416 ± 3.211 ns/op
> ClassGetMethod.getSuperNoArg avgt 6 138.102 ± 16.215 ns/op
>
> (faster in some cases, slower in others)
>
> With paramCount, then name, then Arrays.equals():
>
> Benchmark Mode Cnt Score Error Units
> ClassGetMethod.getConcreteFiveArg avgt 6 95.117 ± 1.574 ns/op
> ClassGetMethod.getConcreteNoArg avgt 6 77.915 ± 10.294 ns/op
> ClassGetMethod.getIntfFiveArg avgt 6 193.514 ± 4.611 ns/op
> ClassGetMethod.getIntfNoArg avgt 6 205.957 ± 4.475 ns/op
> ClassGetMethod.getNoSuchMethod avgt 10 2234.166 ± 51.249 ns/op
> ClassGetMethod.getSuperFiveArg avgt 6 164.650 ± 3.689 ns/op
> ClassGetMethod.getSuperNoArg avgt 6 128.969 ± 4.442 ns/op
>
> (faster or neutral in all cases)
>
> With paramCount, then name, then custom loop:
>
> Benchmark Mode Cnt Score Error Units
> ClassGetMethod.getConcreteFiveArg avgt 6 64.802 ± 4.504 ns/op
> ClassGetMethod.getConcreteNoArg avgt 6 51.998 ± 5.645 ns/op
> ClassGetMethod.getIntfFiveArg avgt 6 194.252 ± 7.759 ns/op
> ClassGetMethod.getIntfNoArg avgt 6 199.110 ± 4.163 ns/op
> ClassGetMethod.getNoSuchMethod avgt 1...
I don't like the style of a custom loop rather than `Arrays.equals()` but there
is a perf benefit to it. Curious what you think?
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/21929#discussion_r1831450140
