On Wed, 14 May 2025 19:37:37 GMT, Archie Cobbs <aco...@openjdk.org> wrote:
> Please review this small performance tweak `ArrayDeque`. > > `ArrayDeque` has an invariant in which any unused elements in the array must > be null. In a couple of places, the code is setting contiguous ranges of > elements to null using `for()` loops. This can be both simplified and sped up > by using `Arrays.fill()` instead. I added a benchmark to the PR (hopefully I did that right). It shows a _decrease_ in performance. I have no idea why. I did this on my laptop so who knows, but if the effect is real then it kind of raises a lot of larger questions. jdk-25+22-94-g0318e49500e (master): Benchmark Mode Cnt Score Error Units ArrayDeque.ClearBenchmarkTestJMH.fillAndClear thrpt 50 37.064 ± 0.225 ops/s jdk-25+22-95-g84fb0903be0 (JDK-8356993): Benchmark Mode Cnt Score Error Units ArrayDeque.ClearBenchmarkTestJMH.fillAndClear thrpt 50 35.528 ± 0.180 ops/s ------------- PR Comment: https://git.openjdk.org/jdk/pull/25237#issuecomment-2884609647
