On Mon, 24 Nov 2025 13:05:40 GMT, Francesco Nigro <[email protected]> wrote:
> This is boosting VirtualThread allocations while using > https://docs.oracle.com/en/java/javase/25/docs/api/java.base/java/lang/Thread.Builder.OfVirtual.html#name(java.lang.String,long) > > The pattern has been discovered on > https://github.com/quarkusio/quarkus/issues/51201 and narrowed down in > https://github.com/franz1981/java-puzzles/commit/5cb4216e8d56cdc6c3c23629419158550cbd9068 > > which, on my machine (Ryzen 7950 w fixed frequency at 4.2 GHz): > > Benchmark Mode > Cnt Score Error Units > VarHandlePolymorphicSignatureSensitivity.rightVarHandle avgt > 10 1.852 ± 0.007 ns/op > VarHandlePolymorphicSignatureSensitivity.rightVarHandleConcatIndy avgt > 10 9.891 ± 0.103 ns/op > VarHandlePolymorphicSignatureSensitivity.wrongVarHandle avgt > 10 10.430 ± 0.045 ns/op > VarHandlePolymorphicSignatureSensitivity.wrongVarHandleConcatIndy avgt > 10 19.312 ± 0.619 ns/op > > where the `right` indy shows: > <img width="1915" height="469" alt="image" > src="https://github.com/user-attachments/assets/4c836389-492b-4cc6-94a3-849f8cf6ea09"; > /> > > vs the `wrong` one: > <img width="1915" height="469" alt="image" > src="https://github.com/user-attachments/assets/73765060-8e95-42a2-a03a-4f53f927a8b8"; > /> This pull request has now been integrated. Changeset: 1226873a Author: Francesco Nigro <[email protected]> Committer: Alan Bateman <[email protected]> URL: https://git.openjdk.org/jdk/commit/1226873ab94d2cc341ddb7040aa60c3bf3614feb Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod 8372410: ThreadFactory used by Thread.Builder::factory uses non-optimal VarHandle Reviewed-by: alanb, adinn, liach ------------- PR: https://git.openjdk.org/jdk/pull/28475
