Integrated: 8269665: Clean-up toString() methods of some primitive wrappers

[Сергей Цыпанов]

On Wed, 30 Jun 2021 08:40:21 GMT, Сергей Цыпанов <github.com+10835776+stsypanov at 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

This pull request has now been integrated.

Changeset: 72145f3b
Author:    Sergey Tsypanov <sergei.tsypanov at yandex.ru>
Committer: Claes Redestad <redestad at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/72145f3b9472c8f5f64f9b9ac93e3331e646f15a
Stats:     13 lines in 4 files changed: 4 ins; 0 del; 9 mod

8269665: Clean-up toString() methods of some primitive wrappers

Reviewed-by: redestad

-------------

PR: https://git.openjdk.java.net/jdk/pull/4633