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8302163: Speed up various String comparison methods with ArraysSupport.mismatch

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Reviewed-by: stsypanov, rriggs, alanb
This commit is contained in:
Claes Redestad 2023-02-15 21:52:41 +00:00
parent 50dcc2aec5
commit 861e302011
5 changed files with 127 additions and 64 deletions
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60
src/java.base/share/classes/java/lang/String.java
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@ -51,6 +51,7 @@ import java.util.stream.IntStream;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
import jdk.internal.util.ArraysSupport;
import jdk.internal.util.Preconditions;
import jdk.internal.vm.annotation.ForceInline;
import jdk.internal.vm.annotation.IntrinsicCandidate;
@ -1272,8 +1273,7 @@ public final class String
}
private static void throwUnmappable(byte[] val) {
int dp = 0;
while (dp < val.length && val[dp] >=0) { dp++; }
int dp = StringCoding.countPositives(val, 0, val.length);
throwUnmappable(dp);
}
@ -1870,23 +1870,17 @@ public final class String
if (len != sb.length()) {
return false;
}
byte v1[] = value;
byte v2[] = sb.getValue();
byte[] v1 = value;
byte[] v2 = sb.getValue();
byte coder = coder();
if (coder == sb.getCoder()) {
int n = v1.length;
for (int i = 0; i < n; i++) {
if (v1[i] != v2[i]) {
return false;
}
}
return v1.length <= v2.length && ArraysSupport.mismatch(v1, v2, v1.length) < 0;
} else {
if (coder != LATIN1) { // utf16 str and latin1 abs can never be "equal"
return false;
}
return StringUTF16.contentEquals(v1, v2, len);
}
return true;
}
/**
@ -2024,8 +2018,8 @@ public final class String
* lexicographically greater than the string argument.
*/
public int compareTo(String anotherString) {
byte v1[] = value;
byte v2[] = anotherString.value;
byte[] v1 = value;
byte[] v2 = anotherString.value;
byte coder = coder();
if (coder == anotherString.coder()) {
return coder == LATIN1 ? StringLatin1.compareTo(v1, v2)
@ -2060,8 +2054,8 @@ public final class String
private static final long serialVersionUID = 8575799808933029326L;
public int compare(String s1, String s2) {
byte v1[] = s1.value;
byte v2[] = s2.value;
byte[] v1 = s1.value;
byte[] v2 = s2.value;
byte coder = s1.coder();
if (coder == s2.coder()) {
return coder == LATIN1 ? StringLatin1.compareToCI(v1, v2)
@ -2136,26 +2130,23 @@ public final class String
* {@code false} otherwise.
*/
public boolean regionMatches(int toffset, String other, int ooffset, int len) {
byte tv[] = value;
byte ov[] = other.value;
// Note: toffset, ooffset, or len might be near -1>>>1.
if ((ooffset < 0) || (toffset < 0) ||
(toffset > (long)length() - len) ||
(ooffset > (long)other.length() - len)) {
return false;
}
byte[] tv = value;
byte[] ov = other.value;
byte coder = coder();
if (coder == other.coder()) {
if (!isLatin1() && (len > 0)) {
toffset = toffset << 1;
ooffset = ooffset << 1;
len = len << 1;
}
while (len-- > 0) {
if (tv[toffset++] != ov[ooffset++]) {
return false;
}
if (coder == UTF16) {
toffset <<= UTF16;
ooffset <<= UTF16;
len <<= UTF16;
}
return ArraysSupport.mismatch(tv, toffset,
ov, ooffset, len) < 0;
} else {
if (coder == LATIN1) {
while (len-- > 0) {
@ -2235,8 +2226,8 @@ public final class String
|| (ooffset > (long)other.length() - len)) {
return false;
}
byte tv[] = value;
byte ov[] = other.value;
byte[] tv = value;
byte[] ov = other.value;
byte coder = coder();
if (coder == other.coder()) {
return coder == LATIN1
@ -2270,18 +2261,17 @@ public final class String
if (toffset < 0 || toffset > length() - prefix.length()) {
return false;
}
byte ta[] = value;
byte pa[] = prefix.value;
byte[] ta = value;
byte[] pa = prefix.value;
int po = 0;
int pc = pa.length;
byte coder = coder();
if (coder == prefix.coder()) {
int to = (coder == LATIN1) ? toffset : toffset << 1;
while (po < pc) {
if (ta[to++] != pa[po++]) {
return false;
}
if (coder == UTF16) {
toffset <<= UTF16;
}
return ArraysSupport.mismatch(ta, toffset,
pa, 0, pc) < 0;
} else {
if (coder == LATIN1) { // && pcoder == UTF16
return false;

8
src/java.base/share/classes/java/lang/StringLatin1.java
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@ -109,12 +109,8 @@ final class StringLatin1 {
public static int compareTo(byte[] value, byte[] other, int len1, int len2) {
int lim = Math.min(len1, len2);
for (int k = 0; k < lim; k++) {
if (value[k] != other[k]) {
return getChar(value, k) - getChar(other, k);
}
}
return len1 - len2;
int k = ArraysSupport.mismatch(value, other, lim);
return (k < 0) ? len1 - len2 : getChar(value, k) - getChar(other, k);
}
@IntrinsicCandidate

13
test/micro/org/openjdk/bench/java/lang/StringBuilders.java
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@ -51,7 +51,9 @@ public class StringBuilders {
private String[] str3p9p8;
private String[] str22p40p31;
private StringBuilder sbLatin1;
private StringBuilder sbLatin2;
private StringBuilder sbUtf16;
private StringBuilder sbUtf17;
@Setup
public void setup() {
@ -64,7 +66,9 @@ public class StringBuilders {
str3p9p8 = new String[]{"123", "123456789", "12345678"};
str22p40p31 = new String[]{"1234567890123456789012", "1234567890123456789012345678901234567890", "1234567890123456789012345678901"};
sbLatin1 = new StringBuilder("Latin1 string");
sbLatin2 = new StringBuilder("Latin1 string");
sbUtf16 = new StringBuilder("UTF-\uFF11\uFF16 string");
sbUtf17 = new StringBuilder("UTF-\uFF11\uFF16 string");
}
@Benchmark
@ -250,6 +254,15 @@ public class StringBuilders {
return result.toString();
}
@Benchmark
public int compareToLatin1() {
return sbLatin1.compareTo(sbLatin2);
}
@Benchmark
public int compareToUTF16() {
return sbUtf16.compareTo(sbUtf17);
}
@Benchmark
public String toStringCharWithMixed8() {

87
test/micro/org/openjdk/bench/java/lang/StringComparisons.java Normal file
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@ -0,0 +1,87 @@
/*
* Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package org.openjdk.bench.java.lang;
import org.openjdk.jmh.annotations.*;
import java.util.concurrent.TimeUnit;
/*
* This benchmark naively explores String::startsWith and other String
* comparison methods
*/
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@State(Scope.Benchmark)
@Warmup(iterations = 5, time = 1)
@Measurement(iterations = 5, time = 1)
@Fork(value = 3)
public class StringComparisons {
@Param({"6", "15", "1024"})
public int size;
@Param({"true", "false"})
public boolean utf16;
public String string;
public String equalString;
public String endsWithA;
public String endsWithB;
public String startsWithA;
@Setup
public void setup() {
String c = utf16 ? "\uff11" : "c";
string = c.repeat(size);
equalString = c.repeat(size);
endsWithA = c.repeat(size).concat("A");
endsWithB = c.repeat(size).concat("B");
startsWithA = "A" + (c.repeat(size));
}
@Benchmark
public boolean startsWith() {
return endsWithA.startsWith(string);
}
@Benchmark
public boolean endsWith() {
return startsWithA.endsWith(string);
}
@Benchmark
public boolean regionMatches() {
return endsWithA.regionMatches(0, endsWithB, 0, endsWithB.length());
}
@Benchmark
public boolean regionMatchesRange() {
return startsWithA.regionMatches(1, endsWithB, 0, endsWithB.length() - 1);
}
@Benchmark
public boolean regionMatchesCI() {
return endsWithA.regionMatches(true, 0, endsWithB, 0, endsWithB.length());
}
}

23
test/micro/org/openjdk/bench/java/lang/StringOther.java
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@ -49,17 +49,9 @@ public class StringOther {
private String testString;
private Random rnd;
private String str1, str2, str3, str4;
private String str1UP;
@Setup
public void setup() {
testString = "Idealism is what precedes experience; cynicism is what follows.";
str1 = "vm-guld vm-guld vm-guld";
str1UP = str1.toUpperCase(Locale.ROOT);
str2 = "vm-guld vm-guld vm-guldx";
str3 = "vm-guld vm-guld vm-guldx";
str4 = "adadaskasdjierudks";
rnd = new Random();
}
@ -70,15 +62,6 @@ public class StringOther {
}
}
@Benchmark
public int compareTo() {
int total = 0;
total += str1.compareTo(str2);
total += str2.compareTo(str3);
total += str3.compareTo(str4);
return total;
}
/**
* Creates (hopefully) unique Strings and internizes them, creating a zillion forgettable strings in the JVMs string
* pool.
@ -94,10 +77,4 @@ public class StringOther {
return String.valueOf(rnd.nextInt()).intern();
}
@Benchmark
public void regionMatchesLatin1(Blackhole bh) {
bh.consume(str1.regionMatches(true, 0, str2, 0, str1.length()));
bh.consume(str2.regionMatches(true, 16, str1UP, 0, 8));
bh.consume(str3.regionMatches(true, 6, str4, 1, 2));
}
}