On Tue, 26 Apr 2022 10:57:04 GMT, Claes Redestad <redes...@openjdk.org> wrote:
> The `MethodType.genericMethodType` methods provide convenience methods for
> certain common method types and also provide `@Stable` cache that allows for
> constant folding. This patch enhances the more generic `methodType` methods
> to take advantage of this cache, when possible. This allows calls like
> `MethodType.methodType(Object.class, Object.class, ...)` to constant fold,
> making them 50x+ faster and allocation-free.
>
> Baseline:
>
> Benchmark Mode Cnt Score Error Units
> MethodTypeAcquire.baselineRaw avgt 15 0.673 ? 0.017 ns/op
> MethodTypeAcquire.testGenericObject avgt 15 0.579 ? 0.125 ns/op
> MethodTypeAcquire.testMultiPType avgt 15 46.671 ? 1.134 ns/op
> MethodTypeAcquire.testMultiPType_Arg avgt 15 27.019 ? 0.437 ns/op
> MethodTypeAcquire.testMultiPType_ObjectAndA avgt 15 57.217 ? 0.505 ns/op
> MethodTypeAcquire.testMultiPType_ObjectOnly avgt 15 57.114 ? 1.214 ns/op
> MethodTypeAcquire.testObjectObject avgt 15 33.380 ? 1.810 ns/op
> MethodTypeAcquire.testReturnInt avgt 15 28.043 ? 0.187 ns/op
> MethodTypeAcquire.testReturnObject avgt 15 24.313 ? 0.074 ns/op
> MethodTypeAcquire.testReturnVoid avgt 15 24.360 ? 0.155 ns/op
> MethodTypeAcquire.testSinglePType avgt 15 33.572 ? 1.101 ns/op
>
>
> Patched:
>
> Benchmark Mode Cnt Score Error Units
> MethodTypeAcquire.baselineRaw avgt 15 0.683 ? 0.024 ns/op
> MethodTypeAcquire.testGenericObject avgt 15 0.547 ? 0.047 ns/op
> MethodTypeAcquire.testMultiPType avgt 15 48.532 ? 0.982 ns/op
> MethodTypeAcquire.testMultiPType_Arg avgt 15 31.390 ? 5.269 ns/op
> MethodTypeAcquire.testMultiPType_ObjectAndA avgt 15 60.165 ? 2.756 ns/op
> MethodTypeAcquire.testMultiPType_ObjectOnly avgt 15 0.599 ? 0.166 ns/op
> MethodTypeAcquire.testObjectObject avgt 15 0.541 ? 0.045 ns/op
> MethodTypeAcquire.testReturnInt avgt 15 28.174 ? 0.257 ns/op
> MethodTypeAcquire.testReturnObject avgt 15 0.542 ? 0.045 ns/op
> MethodTypeAcquire.testReturnVoid avgt 15 24.621 ? 0.202 ns/op
> MethodTypeAcquire.testSinglePType avgt 15 33.614 ? 1.109 ns/op
>
>
> The cost on method types that don't match are in the noise (0-2ns/op). Even
> on a test I constructed to act as a worst case (`testMultiPType_ObjectAndA`)
> there's barely any appreciable cost (~3ns/op, with overlapping error).
Marked as reviewed by jvernee (Reviewer).
test/micro/org/openjdk/bench/java/lang/invoke/MethodTypeAcquire.java line 104:
> 102: @Benchmark
> 103: public MethodType testMultiPType_ObjectOnly() {
> 104: return MethodType.methodType(Object.class, Object.class,
> Object.class, Object.class, Object.class, Object.class, Object.class);
It might be interesting to add a benchmark where all types are `Object`, but
non-constants, to see if that case improves as well.
-------------
PR: https://git.openjdk.java.net/jdk/pull/8398
