Re: RFR: 8255299: Drop explicit zeroing at instantiation of Atomic* objects [v2]
On Wed, 28 Oct 2020 08:56:05 GMT, Сергей Цыпанов wrote: >> FYI it is better to use merge, instead of rebase+force push. Rebase breaks >> history and all existed code comments. > > @mrserb thanks for pointing this out! Thanks for updating with latest master changes Sergey! My tests were all green. - PR: https://git.openjdk.java.net/jdk/pull/818
Re: RFR: 8255299: Drop explicit zeroing at instantiation of Atomic* objects [v2]
On Wed, 28 Oct 2020 08:49:38 GMT, Sergey Bylokhov wrote: >> Rebased onto master to have the fix introduced in >> https://github.com/openjdk/jdk/pull/778 > > FYI it is better to use merge, instead of rebase+force push. Rebase breaks > history and all existed code comments. @mrserb thanks for pointing this out! - PR: https://git.openjdk.java.net/jdk/pull/818
Re: RFR: 8255299: Drop explicit zeroing at instantiation of Atomic* objects [v2]
On Wed, 28 Oct 2020 08:40:02 GMT, Сергей Цыпанов wrote: >> client changes are fine > > Rebased onto master to have the fix introduced in > https://github.com/openjdk/jdk/pull/778 FYI it is better to use merge, instead of rebase+force push. Rebase breaks history and all existed code comments. - PR: https://git.openjdk.java.net/jdk/pull/818
Re: RFR: 8255299: Drop explicit zeroing at instantiation of Atomic* objects [v2]
On Sat, 24 Oct 2020 23:12:09 GMT, Phil Race wrote: >> 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 > > client changes are fine Rebased onto master to have the fix introduced in https://github.com/openjdk/jdk/pull/778 - PR: https://git.openjdk.java.net/jdk/pull/818
Re: RFR: 8255299: Drop explicit zeroing at instantiation of Atomic* objects [v2]
> 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
