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/*
* Copyright (C) 2016 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 System.arraycopy intrinsics.
* Main Focus: Looped load store for varying copy lengths.
* Secondary Focus:
*
*/
package org.linaro.benchmarks.micro;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.StringReader;
import java.lang.StringBuilder;
import java.lang.System;
import java.util.Random;
import org.openjdk.jmh.annotations.*;
import java.util.concurrent.TimeUnit;
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@State(Scope.Benchmark)
public class SystemArrayCopy {
private static Random rnd = new Random();
private static int ARRAY_COPY_SMALL = 16;
private static int ARRAY_COPY_MEDIUM = 128;
private static int ARRAY_COPY_LARGE = 1024;
private static int MAX_BUFFER_BYTES = 8192;
private static int ARRAY_LENGTH = 1024;
private static String RANDOM_STRING = generateRandomString(MAX_BUFFER_BYTES);
private static char[] cbuf = new char[MAX_BUFFER_BYTES];
private static char arrayCopyCharBufferedReadSmallResult;
private static char arrayCopyCharBufferedReadMediumResult;
private static char arrayCopyCharBufferedReadLargeResult;
private static String[] stringArray = new String[ARRAY_LENGTH];
private static String[] stringArraySmall = new String[ARRAY_LENGTH];
private static String[] stringArrayMedium = new String[ARRAY_LENGTH];
private static String[] stringArrayLarge = new String[ARRAY_LENGTH];
private static String generateRandomString(int sz) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < sz; i++) {
sb.append(Character.valueOf((char)rnd.nextInt()));
}
return sb.toString();
}
static {
for (int i = 0; i < ARRAY_LENGTH; i++) {
stringArray[i] = String.valueOf(i);
}
}
private void bufferedReadLoop(char[] cbuf, int copyLength) throws IOException {
BufferedReader reader = new BufferedReader(new StringReader(RANDOM_STRING));
int offset = 0;
String s;
/* Read 16Kb RANDOM_STRING in chunks of copyLength chars until EOF */
while (offset < MAX_BUFFER_BYTES && (reader.read(cbuf, offset, copyLength)) != -1) {
offset += copyLength;
}
}
@Benchmark
public void jmhTimeArrayCopyCharBufferedReadSmall() throws IOException {
bufferedReadLoop(cbuf, ARRAY_COPY_SMALL);
arrayCopyCharBufferedReadSmallResult = cbuf[MAX_BUFFER_BYTES - 1];
}
@Benchmark
public void jmhTimeArrayCopyCharBufferedReadMedium() throws IOException {
bufferedReadLoop(cbuf, ARRAY_COPY_MEDIUM);
arrayCopyCharBufferedReadMediumResult = cbuf[MAX_BUFFER_BYTES - 1];
}
@Benchmark
public void jmhTimeArrayCopyCharBufferedReadLarge() throws IOException {
bufferedReadLoop(cbuf, ARRAY_COPY_LARGE);
arrayCopyCharBufferedReadLargeResult = cbuf[MAX_BUFFER_BYTES - 1];
}
@Benchmark
public void jmhTimeArrayCopySmall() {
System.arraycopy(stringArray, 0, stringArraySmall, 0, ARRAY_COPY_SMALL);
}
@Benchmark
public void jmhTimeArrayCopyMedium() {
System.arraycopy(stringArray, 0, stringArrayMedium, 0, ARRAY_COPY_MEDIUM);
}
@Benchmark
public void jmhTimeArrayCopyLarge() {
System.arraycopy(stringArray, 0, stringArrayLarge, 0, ARRAY_COPY_LARGE);
}
}
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