/*
* Copyright (c) 2008-2017, Hazelcast, Inc. 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.
*/
package com.hazelcast.internal.networking.nio.iobalancer;
import com.hazelcast.internal.networking.nio.MigratableHandler;
import com.hazelcast.internal.networking.nio.NioThread;
import com.hazelcast.test.HazelcastParallelClassRunner;
import com.hazelcast.test.HazelcastTestSupport;
import com.hazelcast.test.annotation.ParallelTest;
import com.hazelcast.test.annotation.QuickTest;
import com.hazelcast.util.ItemCounter;
import org.junit.Before;
import org.junit.Test;
import org.junit.experimental.categories.Category;
import org.junit.runner.RunWith;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import static com.hazelcast.test.TestCollectionUtils.setOf;
import static java.lang.Math.abs;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;
import static org.mockito.Mockito.mock;
@RunWith(HazelcastParallelClassRunner.class)
@Category({QuickTest.class, ParallelTest.class})
public class MonkeyMigrationStrategyTest extends HazelcastTestSupport {
private MigrationStrategy strategy;
private Map<NioThread, Set<MigratableHandler>> selectorToHandlers;
private ItemCounter<MigratableHandler> handlerEventsCounter;
private LoadImbalance imbalance;
@Test
public void imbalanceDetected_shouldReturnFalseWhenNoHandlerExist() {
selectorToHandlers.put(imbalance.sourceSelector, Collections.<MigratableHandler>emptySet());
boolean imbalanceDetected = strategy.imbalanceDetected(imbalance);
assertFalse(imbalanceDetected);
}
@Before
public void setUp() {
selectorToHandlers = new HashMap<NioThread, Set<MigratableHandler>>();
handlerEventsCounter = new ItemCounter<MigratableHandler>();
imbalance = new LoadImbalance(selectorToHandlers, handlerEventsCounter);
imbalance.sourceSelector = mock(NioThread.class);
this.strategy = new MonkeyMigrationStrategy();
}
@Test
public void imbalanceDetected_shouldReturnTrueWhenHandlerExist() {
MigratableHandler handler = mock(MigratableHandler.class);
selectorToHandlers.put(imbalance.sourceSelector, setOf(handler));
boolean imbalanceDetected = strategy.imbalanceDetected(imbalance);
assertTrue(imbalanceDetected);
}
@Test
public void findHandlerToMigrate_shouldWorkEvenWithASingleHandlerAvailable() {
MigratableHandler handler = mock(MigratableHandler.class);
selectorToHandlers.put(imbalance.sourceSelector, setOf(handler));
MigratableHandler handlerToMigrate = strategy.findHandlerToMigrate(imbalance);
assertEquals(handler, handlerToMigrate);
}
@Test
public void findHandlerToMigrate_shouldBeFair() {
int iterationCount = 10000;
double toleranceFactor = 0.25d;
MigratableHandler handler1 = mock(MigratableHandler.class);
MigratableHandler handler2 = mock(MigratableHandler.class);
selectorToHandlers.put(imbalance.sourceSelector, setOf(handler1, handler2));
assertFairSelection(iterationCount, toleranceFactor, handler1, handler2);
}
private void assertFairSelection(int iterationCount, double toleranceFactor, MigratableHandler handler1, MigratableHandler handler2) {
int handler1Count = 0;
int handler2Count = 0;
for (int i = 0; i < iterationCount; i++) {
MigratableHandler candidate = strategy.findHandlerToMigrate(imbalance);
if (candidate == handler1) {
handler1Count++;
} else if (candidate == handler2) {
handler2Count++;
} else {
fail("No handler selected");
}
}
int diff = abs(handler1Count - handler2Count);
assertTrue(diff < (iterationCount * toleranceFactor));
}
}