/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
package org.apache.hadoop.raid;
import java.util.HashSet;
import java.util.Random;
import java.util.Set;
import junit.framework.TestCase;
public class TestErasureCodes extends TestCase {
final int TEST_CODES = 100;
final int TEST_TIMES = 1000;
final Random RAND = new Random();
public void testEncodeDecode() {
for (int n = 0; n < TEST_CODES; n++) {
int stripeSize = RAND.nextInt(99) + 1; // 1, 2, 3, ... 100
int paritySize = RAND.nextInt(9) + 1; //1, 2, 3, 4, ... 10
ErasureCode ec = new ReedSolomonCode(stripeSize, paritySize);
for (int m = 0; m < TEST_TIMES; m++) {
int symbolMax = (int) Math.pow(2, ec.symbolSize());
int[] message = new int[stripeSize];
for (int i = 0; i < stripeSize; i++) {
message[i] = RAND.nextInt(symbolMax);
}
int[] parity = new int[paritySize];
ec.encode(message, parity);
int[] data = new int[stripeSize + paritySize];
int[] copy = new int[data.length];
for (int i = 0; i < paritySize; i++) {
data[i] = parity[i];
copy[i] = parity[i];
}
for (int i = 0; i < stripeSize; i++) {
data[i + paritySize] = message[i];
copy[i + paritySize] = message[i];
}
int erasedLen = paritySize == 1 ? 1 : RAND.nextInt(paritySize - 1) + 1;
int[] erasedLocations = randomErasedLocation(erasedLen, data.length);
for (int i = 0; i < erasedLocations.length; i++) {
data[erasedLocations[i]] = 0;
}
int[] erasedValues = new int[erasedLen];
ec.decode(data, erasedLocations, erasedValues);
for (int i = 0; i < erasedLen; i++) {
assertEquals("Decode failed", copy[erasedLocations[i]], erasedValues[i]);
}
}
}
}
public void testRSPerformance() {
int stripeSize = 10;
int paritySize = 4;
ErasureCode ec = new ReedSolomonCode(stripeSize, paritySize);
int symbolMax = (int) Math.pow(2, ec.symbolSize());
byte[][] message = new byte[stripeSize][];
int bufsize = 1024 * 1024 * 10;
for (int i = 0; i < stripeSize; i++) {
message[i] = new byte[bufsize];
for (int j = 0; j < bufsize; j++) {
message[i][j] = (byte) RAND.nextInt(symbolMax);
}
}
byte[][] parity = new byte[paritySize][];
for (int i = 0; i < paritySize; i++) {
parity[i] = new byte[bufsize];
}
long encodeStart = System.currentTimeMillis();
int[] tmpIn = new int[stripeSize];
int[] tmpOut = new int[paritySize];
for (int i = 0; i < bufsize; i++) {
// Copy message.
for (int j = 0; j < stripeSize; j++) tmpIn[j] = 0x000000FF & message[j][i];
ec.encode(tmpIn, tmpOut);
// Copy parity.
for (int j = 0; j < paritySize; j++) parity[j][i] = (byte)tmpOut[j];
}
long encodeEnd = System.currentTimeMillis();
float encodeMSecs = (encodeEnd - encodeStart);
System.out.println("Time to encode rs = " + encodeMSecs +
"msec (" + message[0].length / (1000 * encodeMSecs) + " MB/s)");
// Copy erased array.
int[] data = new int[paritySize + stripeSize];
// 4th location is the 0th symbol in the message
int[] erasedLocations = new int[]{4, 1, 5, 7};
int[] erasedValues = new int[erasedLocations.length];
byte[] copy = new byte[bufsize];
for (int j = 0; j < bufsize; j++) {
copy[j] = message[0][j];
message[0][j] = 0;
}
long decodeStart = System.currentTimeMillis();
for (int i = 0; i < bufsize; i++) {
// Copy parity first.
for (int j = 0; j < paritySize; j++) {
data[j] = 0x000000FF & parity[j][i];
}
// Copy message. Skip 0 as the erased symbol
for (int j = 1; j < stripeSize; j++) {
data[j + paritySize] = 0x000000FF & message[j][i];
}
// Use 0, 2, 3, 6, 8, 9, 10, 11, 12, 13th symbol to reconstruct the data
ec.decode(data, erasedLocations, erasedValues);
message[0][i] = (byte)erasedValues[0];
}
long decodeEnd = System.currentTimeMillis();
float decodeMSecs = (decodeEnd - decodeStart);
System.out.println("Time to decode = " + decodeMSecs +
"msec (" + message[0].length / (1000 * decodeMSecs) + " MB/s)");
assertTrue("Decode failed", java.util.Arrays.equals(copy, message[0]));
}
public void testXorPerformance() {
java.util.Random RAND = new java.util.Random();
int stripeSize = 10;
byte[][] message = new byte[stripeSize][];
int bufsize = 1024 * 1024 * 10;
for (int i = 0; i < stripeSize; i++) {
message[i] = new byte[bufsize];
for (int j = 0; j < bufsize; j++) {
message[i][j] = (byte)RAND.nextInt(256);
}
}
byte[] parity = new byte[bufsize];
long encodeStart = System.currentTimeMillis();
for (int i = 0; i < bufsize; i++) {
for (int j = 0; j < stripeSize; j++) parity[i] ^= message[j][i];
}
long encodeEnd = System.currentTimeMillis();
float encodeMSecs = encodeEnd - encodeStart;
System.out.println("Time to encode xor = " + encodeMSecs +
" msec (" + message[0].length / (1000 * encodeMSecs) + "MB/s)");
byte[] copy = new byte[bufsize];
for (int j = 0; j < bufsize; j++) {
copy[j] = message[0][j];
message[0][j] = 0;
}
long decodeStart = System.currentTimeMillis();
for (int i = 0; i < bufsize; i++) {
for (int j = 1; j < stripeSize; j++) message[0][i] ^= message[j][i];
message[0][i] ^= parity[i];
}
long decodeEnd = System.currentTimeMillis();
float decodeMSecs = decodeEnd - decodeStart;
System.out.println("Time to decode xor = " + decodeMSecs +
" msec (" + message[0].length / (1000 * decodeMSecs) + "MB/s)");
assertTrue("Decode failed", java.util.Arrays.equals(copy, message[0]));
}
private int[] randomErasedLocation(int erasedLen, int dataLen) {
int[] erasedLocations = new int[erasedLen];
for (int i = 0; i < erasedLen; i++) {
Set<Integer> s = new HashSet<Integer>();
while (s.size() != erasedLen) {
s.add(RAND.nextInt(dataLen));
}
int t = 0;
for (int erased : s) {
erasedLocations[t++] = erased;
}
}
return erasedLocations;
}
}