On Mon, 2 Aug 2021 12:29:00 GMT, Сергей Цыпанов
<github.com+10835776+stsypa...@openjdk.org> wrote:
>> As of JDK 17 some of primitive wrappers, e.g. `Long`, `Integer`, `Double`
>> and `Float` in their implementations of `Object.toString()` delegate to own
>> utility `toString(primitive)` methods.
>>
>> Unlike those, `Boolean`, `Byte`, `Character` and `Short` just duplicate the
>> contents of utility methods in implementations of `Object.toString()`.
>>
>> Yet another issue is a tiny discrepancy in implementation related to `Byte`
>> and `Short` (see the first):
>>
>> public static String toString(byte b) {
>> return Integer.toString((int)b, 10);
>> }
>>
>> public String toString() {
>> return Integer.toString((int)value);
>> }
>>
>> Unlike in overriden method, In utility one they explicitly specify radix
>> which can be skipped, as implementation of `Integer.toString(int,int)` has a
>> fast-path for radix 10, ending in `Integer.toString(int)`. This
>> simplification gives tiny improvement, see benchmark:
>>
>> @BenchmarkMode(Mode.AverageTime)
>> @OutputTimeUnit(TimeUnit.NANOSECONDS)
>> @Fork(jvmArgsAppend = {"-Xms2g", "-Xmx2g"})
>> public class ByteToStringBenchmark {
>> @Benchmark
>> public String byteToString() {
>> return Byte.toString((byte) 1);
>> }
>> }
>>
>> Results:
>>
>> before
>>
>> Benchmark Mode
>> Cnt Score Error Units
>> ByteToStringBenchmark.byteToString avgt
>> 30 11,648 ± 1,906 ns/op
>> ByteToStringBenchmark.byteToString:·gc.alloc.rate avgt
>> 30 3288,576 ± 418,119 MB/sec
>> ByteToStringBenchmark.byteToString:·gc.alloc.rate.norm avgt
>> 30 48,001 ± 0,001 B/op
>> ByteToStringBenchmark.byteToString:·gc.churn.G1_Eden_Space avgt
>> 30 3301,804 ± 455,932 MB/sec
>> ByteToStringBenchmark.byteToString:·gc.churn.G1_Eden_Space.norm avgt
>> 30 48,158 ± 2,085 B/op
>> ByteToStringBenchmark.byteToString:·gc.churn.G1_Survivor_Space avgt
>> 30 0,004 ± 0,001 MB/sec
>> ByteToStringBenchmark.byteToString:·gc.churn.G1_Survivor_Space.norm avgt
>> 30 ≈ 10⁻⁴ B/op
>> ByteToStringBenchmark.byteToString:·gc.count avgt
>> 30 202,000 counts
>> ByteToStringBenchmark.byteToString:·gc.time avgt
>> 30 413,000 ms
>>
>> after
>>
>> Benchmark Mode
>> Cnt Score Error Units
>> ByteToStringBenchmark.byteToString avgt
>> 30 10,016 ± 0,530 ns/op
>> ByteToStringBenchmark.byteToString:·gc.alloc.rate avgt
>> 30 3673,700 ± 167,450 MB/sec
>> ByteToStringBenchmark.byteToString:·gc.alloc.rate.norm avgt
>> 30 48,001 ± 0,001 B/op
>> ByteToStringBenchmark.byteToString:·gc.churn.G1_Eden_Space avgt
>> 30 3662,406 ± 205,978 MB/sec
>> ByteToStringBenchmark.byteToString:·gc.churn.G1_Eden_Space.norm avgt
>> 30 47,870 ± 1,750 B/op
>> ByteToStringBenchmark.byteToString:·gc.churn.G1_Survivor_Space avgt
>> 30 0,004 ± 0,002 MB/sec
>> ByteToStringBenchmark.byteToString:·gc.churn.G1_Survivor_Space.norm avgt
>> 30 ≈ 10⁻⁴ B/op
>> ByteToStringBenchmark.byteToString:·gc.count avgt
>> 30 224,000 counts
>> ByteToStringBenchmark.byteToString:·gc.time avgt
>> 30 358,000 ms
>
> Сергей Цыпанов has updated the pull request incrementally with one additional
> commit since the last revision:
>
> 8269665: Revert irrelevant changes
Marked as reviewed by redestad (Reviewer).
-------------
PR: https://git.openjdk.java.net/jdk/pull/4633
