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/*
* Copyright (C) 2015 Linaro Limited. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
/*
* Description: Tracks performance of String.equals when working with
* cache-limiting amounts of character data. Some prefetch
* hint investigations have shown a performance gain here.
* Main Focus: Comparison of many, very large (re: L1 cache) strings.
* Secondary Focus:
*
*/
/*
* TODO: Test various sizes of strings.
* TODO: Benchmark other cases, like comparing strings of different
* sizes together (probably the most command case), or similar
* strings that have a run of equal characters to begin with.
*/
package art_benchmarks.micro;
import java.lang.StringBuilder;
import java.util.Random;
public class StringEquals {
private static Random rnd = new Random(0);
private static final int NUM_Equals = 1024;
private static final int STR_Length = 512;
private static String[] randomStrings = new String[NUM_Equals];
private static Boolean[] equalsResults = new Boolean[NUM_Equals - 1];
static {
generateRandomStrings();
}
private static void generateRandomStrings() {
for (int i = 0; i < NUM_Equals; i++) {
StringBuilder sb = new StringBuilder();
for (int j = 0; j < STR_Length; j++) {
sb.append(Character.valueOf((char)(rnd.nextInt(25) + 65)));
}
randomStrings[i] = sb.toString();
}
}
public void timeEquals(int iterations) {
for (int i = 0; i < iterations; i++) {
for (int j = 0; j < NUM_Equals - 1; j++) {
equalsResults[j] = randomStrings[j].equals(randomStrings[j + 1]);
}
}
}
public static void main(String[] args) {
StringEquals eq = new StringEquals();
long before = System.currentTimeMillis();
eq.timeEquals(1500);
eq.timeEquals(1500);
long after = System.currentTimeMillis();
System.out.println("art_benchmarks/micro/StringEquals: " + (after - before));
}
}
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