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8215017: Improve String::equals warmup characteristics

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Reviewed-by: jlaskey
This commit is contained in:
Claes Redestad 2019-04-11 14:56:52 +02:00
parent d0788ec07f
commit 5b2d4559b1
2 changed files with 105 additions and 25 deletions
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56
src/java.base/share/classes/java/lang/String.java
View File

@ -1020,9 +1020,8 @@ public final class String
}
if (anObject instanceof String) {
String aString = (String)anObject;
if (coder() == aString.coder()) {
return isLatin1() ? StringLatin1.equals(value, aString.value)
: StringUTF16.equals(value, aString.value);
if (!COMPACT_STRINGS || this.coder == aString.coder) {
return StringLatin1.equals(value, aString.value);
}
}
return false;
@ -1057,7 +1056,8 @@ public final class String
}
byte v1[] = value;
byte v2[] = sb.getValue();
if (coder() == sb.getCoder()) {
byte coder = coder();
if (coder == sb.getCoder()) {
int n = v1.length;
for (int i = 0; i < n; i++) {
if (v1[i] != v2[i]) {
@ -1065,7 +1065,7 @@ public final class String
}
}
} else {
if (!isLatin1()) { // utf16 str and latin1 abs can never be "equal"
if (coder != LATIN1) { // utf16 str and latin1 abs can never be "equal"
return false;
}
return StringUTF16.contentEquals(v1, v2, len);
@ -1209,12 +1209,13 @@ public final class String
public int compareTo(String anotherString) {
byte v1[] = value;
byte v2[] = anotherString.value;
if (coder() == anotherString.coder()) {
return isLatin1() ? StringLatin1.compareTo(v1, v2)
: StringUTF16.compareTo(v1, v2);
byte coder = coder();
if (coder == anotherString.coder()) {
return coder == LATIN1 ? StringLatin1.compareTo(v1, v2)
: StringUTF16.compareTo(v1, v2);
}
return isLatin1() ? StringLatin1.compareToUTF16(v1, v2)
: StringUTF16.compareToLatin1(v1, v2);
return coder == LATIN1 ? StringLatin1.compareToUTF16(v1, v2)
: StringUTF16.compareToLatin1(v1, v2);
}
/**
@ -1238,12 +1239,13 @@ public final class String
public int compare(String s1, String s2) {
byte v1[] = s1.value;
byte v2[] = s2.value;
if (s1.coder() == s2.coder()) {
return s1.isLatin1() ? StringLatin1.compareToCI(v1, v2)
: StringUTF16.compareToCI(v1, v2);
byte coder = s1.coder();
if (coder == s2.coder()) {
return coder == LATIN1 ? StringLatin1.compareToCI(v1, v2)
: StringUTF16.compareToCI(v1, v2);
}
return s1.isLatin1() ? StringLatin1.compareToCI_UTF16(v1, v2)
: StringUTF16.compareToCI_Latin1(v1, v2);
return coder == LATIN1 ? StringLatin1.compareToCI_UTF16(v1, v2)
: StringUTF16.compareToCI_Latin1(v1, v2);
}
/** Replaces the de-serialized object. */
@ -1317,7 +1319,8 @@ public final class String
(ooffset > (long)other.length() - len)) {
return false;
}
if (coder() == other.coder()) {
byte coder = coder();
if (coder == other.coder()) {
if (!isLatin1() && (len > 0)) {
toffset = toffset << 1;
ooffset = ooffset << 1;
@ -1329,7 +1332,7 @@ public final class String
}
}
} else {
if (coder() == LATIN1) {
if (coder == LATIN1) {
while (len-- > 0) {
if (StringLatin1.getChar(tv, toffset++) !=
StringUTF16.getChar(ov, ooffset++)) {
@ -1411,12 +1414,13 @@ public final class String
}
byte tv[] = value;
byte ov[] = other.value;
if (coder() == other.coder()) {
return isLatin1()
byte coder = coder();
if (coder == other.coder()) {
return coder == LATIN1
? StringLatin1.regionMatchesCI(tv, toffset, ov, ooffset, len)
: StringUTF16.regionMatchesCI(tv, toffset, ov, ooffset, len);
}
return isLatin1()
return coder == LATIN1
? StringLatin1.regionMatchesCI_UTF16(tv, toffset, ov, ooffset, len)
: StringUTF16.regionMatchesCI_Latin1(tv, toffset, ov, ooffset, len);
}
@ -1447,15 +1451,16 @@ public final class String
byte pa[] = prefix.value;
int po = 0;
int pc = pa.length;
if (coder() == prefix.coder()) {
int to = isLatin1() ? toffset : toffset << 1;
byte coder = coder();
if (coder == prefix.coder()) {
int to = (coder == LATIN1) ? toffset : toffset << 1;
while (po < pc) {
if (ta[to++] != pa[po++]) {
return false;
}
}
} else {
if (isLatin1()) { // && pcoder == UTF16
if (coder == LATIN1) { // && pcoder == UTF16
return false;
}
// coder == UTF16 && pcoder == LATIN1)
@ -1688,11 +1693,12 @@ public final class String
* or {@code -1} if there is no such occurrence.
*/
public int indexOf(String str) {
if (coder() == str.coder()) {
byte coder = coder();
if (coder == str.coder()) {
return isLatin1() ? StringLatin1.indexOf(value, str.value)
: StringUTF16.indexOf(value, str.value);
}
if (coder() == LATIN1) { // str.coder == UTF16
if (coder == LATIN1) { // str.coder == UTF16
return -1;
}
return StringUTF16.indexOfLatin1(value, str.value);

74
test/micro/org/openjdk/bench/java/lang/StringEquals.java Normal file
View File

@ -0,0 +1,74 @@
/*
* Copyright (c) 2019, 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::equals performance
*/
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@State(Scope.Benchmark)
public class StringEquals {
public String test = new String("0123456789");
public String test2 = new String("tgntogjnrognagronagroangroarngorngaorng");
public String test3 = new String(test); // equal to test, but not same
public String test4 = new String("0123\u01FF");
public String test5 = new String(test4); // equal to test4, but not same
public String test6 = new String("0123456780");
public String test7 = new String("0123\u01FE");
@Benchmark
public boolean different() {
return test.equals(test2);
}
@Benchmark
public boolean equal() {
return test.equals(test3);
}
@Benchmark
public boolean almostEqual() {
return test.equals(test6);
}
@Benchmark
public boolean almostEqualUTF16() {
return test4.equals(test7);
}
@Benchmark
public boolean differentCoders() {
return test.equals(test4);
}
@Benchmark
public boolean equalsUTF16() {
return test5.equals(test4);
}
}