> As discussed in https://github.com/openjdk/jdk/pull/510 there is never a > reason to explicitly instantiate any instance of `Atomic*` class with its > default value, i.e. `new AtomicInteger(0)` could be replaced with `new > AtomicInteger()` which is faster: > @State(Scope.Thread) > @OutputTimeUnit(TimeUnit.NANOSECONDS) > @BenchmarkMode(value = Mode.AverageTime) > public class AtomicBenchmark { > @Benchmark > public Object defaultValue() { > return new AtomicInteger(); > } > @Benchmark > public Object explicitValue() { > return new AtomicInteger(0); > } > } > THis benchmark demonstrates that `explicitValue()` is much slower: > Benchmark Mode Cnt Score Error Units > AtomicBenchmark.defaultValue avgt 30 4.778 ± 0.403 ns/op > AtomicBenchmark.explicitValue avgt 30 11.846 ± 0.273 ns/op > So meanwhile https://bugs.openjdk.java.net/browse/JDK-8145948 is still in > progress we could trivially replace explicit zeroing with default > constructors gaining some performance benefit with no risk. > > I've tested the changes locally, both tier1 and tier 2 are ok. > > Could one create an issue for tracking this?
Сергей Цыпанов has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains one additional commit since the last revision: 8255299: Drop explicit zeroing at instantiation of Atomic* objects ------------- Changes: - all: https://git.openjdk.java.net/jdk/pull/818/files - new: https://git.openjdk.java.net/jdk/pull/818/files/c1fb362f..7dc646d0 Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=818&range=01 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=818&range=00-01 Stats: 4576 lines in 201 files changed: 2659 ins; 1135 del; 782 mod Patch: https://git.openjdk.java.net/jdk/pull/818.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/818/head:pull/818 PR: https://git.openjdk.java.net/jdk/pull/818
