Filed and pushed: https://bugs.openjdk.java.net/browse/JDK-8241649
/Claes
On 2020-03-26 00:12, Roger Riggs wrote:
Agreed, +1
On 3/25/20 5:53 PM, Claes Redestad wrote:
Looks good and trivial, including the drive-by cleanups.
I can sponsor.
/Claes
On 2020-03-25 22:18, Сергей Цыпанов wrote:
Hello,
I think we can reduce allocation rate for j.l.Character.toString() by
calling String.valueOf(char) instead of String.valueOf(char[]).
Current implementation creates char[] with one char which is later
decoded into byte[].
Instead String.valueOf(char) decodes char directly consuming less
memory. I've used benchmark [1]
and on my machine got those results (JDK 14):
Benchmark Mode Score Error Units
CharacterToStringBenchmark.toString_utf8 avgt 14.723 ± 1.354 ns/op
CharacterToStringBenchmark.valueOf_utf8 avgt 7.678 ± 0.601 ns/op
CharacterToStringBenchmark.toString_latin avgt 10.992 ± 1.371 ns/op
CharacterToStringBenchmark.valueOf_latin avgt 7.844 ± 1.044 ns/op
CharacterToStringBenchmark.toString_utf8:·gc.alloc.rate.norm avgt
96.003 ± 0.001 B/op
CharacterToStringBenchmark.valueOf_utf8:·gc.alloc.rate.norm avgt
48.002 ± 0.001 B/op
CharacterToStringBenchmark.toString_latin:·gc.alloc.rate.norm avgt
72.003 ± 0.001 B/op
CharacterToStringBenchmark.valueOf_latin:·gc.alloc.rate.norm avgt
48.002 ± 0.001 B/op
Patch is below.
With best regards,
Sergey Tsypanov
[1]
https://github.com/stsypanov/strings/blob/master/src/jmh/java/tsypanov/strings/character/CharacterToStringBenchmark.java
diff --git a/src/java.base/share/classes/java/lang/Character.java
b/src/java.base/share/classes/java/lang/Character.java
--- a/src/java.base/share/classes/java/lang/Character.java
+++ b/src/java.base/share/classes/java/lang/Character.java
@@ -3285,7 +3285,7 @@
"SYMBOLS AND PICTOGRAPHS EXTENDED-A",
"SYMBOLSANDPICTOGRAPHSEXTENDED-A");
- private static final int blockStarts[] = {
+ private static final int[] blockStarts = {
0x0000, // 0000..007F; Basic Latin
0x0080, // 0080..00FF; Latin-1 Supplement
0x0100, // 0100..017F; Latin Extended-A
@@ -8068,7 +8068,7 @@
UNKNOWN, // E01F0..10FFFF
};
- private static HashMap<String, Character.UnicodeScript>
aliases;
+ private static final HashMap<String,
Character.UnicodeScript> aliases;
static {
aliases = new HashMap<>((int)(153 / 0.75f + 1.0f));
aliases.put("ADLM", ADLAM);
@@ -8421,8 +8421,7 @@
* @return a string representation of this object.
*/
public String toString() {
- char buf[] = {value};
- return String.valueOf(buf);
+ return toString(value);
}
/**
