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Posted to commits@hbase.apache.org by bu...@apache.org on 2019/11/15 04:13:44 UTC
[hbase] branch master updated: HBASE-19450 Add log about average
execution time for ScheduledChore
This is an automated email from the ASF dual-hosted git repository.
busbey pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/hbase.git
The following commit(s) were added to refs/heads/master by this push:
new 67f9afc HBASE-19450 Add log about average execution time for ScheduledChore
67f9afc is described below
commit 67f9afc722b21d67e81e5d70359b7d55c43689de
Author: Reid Chan <re...@outlook.com>
AuthorDate: Thu Dec 14 19:53:25 2017 +0800
HBASE-19450 Add log about average execution time for ScheduledChore
Signed-off-by: Sean Busbey <bu...@apache.org>
---
.../org/apache/hadoop/hbase/ScheduledChore.java | 11 +-
.../hbase/util/ExponentialMovingAverage.java | 79 +++++++++++
.../apache/hadoop/hbase/util/MovingAverage.java | 81 +++++++++++
.../hadoop/hbase/util/SimpleMovingAverage.java | 45 ++++++
.../apache/hadoop/hbase/util/TimeMeasurable.java | 35 +++++
.../hadoop/hbase/util/WeightedMovingAverage.java | 65 +++++++++
.../hadoop/hbase/util/WindowMovingAverage.java | 118 ++++++++++++++++
.../hadoop/hbase/util/TestMovingAverage.java | 152 +++++++++++++++++++++
8 files changed, 585 insertions(+), 1 deletion(-)
diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/ScheduledChore.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/ScheduledChore.java
index 468b5d3..78458d4 100644
--- a/hbase-common/src/main/java/org/apache/hadoop/hbase/ScheduledChore.java
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/ScheduledChore.java
@@ -21,6 +21,8 @@ package org.apache.hadoop.hbase;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
+import org.apache.hadoop.hbase.util.MovingAverage;
+import org.apache.hadoop.hbase.util.WindowMovingAverage;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@@ -79,6 +81,8 @@ public abstract class ScheduledChore implements Runnable {
*/
private final Stoppable stopper;
+ private final MovingAverage<Void> timeMeasurement = new WindowMovingAverage();
+
interface ChoreServicer {
/**
* Cancel any ongoing schedules that this chore has with the implementer of this interface.
@@ -183,7 +187,12 @@ public abstract class ScheduledChore implements Runnable {
if (!initialChoreComplete) {
initialChoreComplete = initialChore();
} else {
- chore();
+ timeMeasurement.measure(() -> {
+ chore();
+ return null;
+ });
+ LOG.info(String.format("%s average execution time: %.2f ns.", getName(),
+ timeMeasurement.getAverageTime()));
}
} catch (Throwable t) {
if (LOG.isErrorEnabled()) LOG.error("Caught error", t);
diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ExponentialMovingAverage.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ExponentialMovingAverage.java
new file mode 100644
index 0000000..ce0c1a3
--- /dev/null
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ExponentialMovingAverage.java
@@ -0,0 +1,79 @@
+/*
+ * 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.hbase.util;
+
+import org.apache.yetus.audience.InterfaceAudience;
+
+/**
+ * EMA is similar to {@link WeightedMovingAverage} in weighted, but the weighting factor decrease
+ * exponentially. It brings benefits that it is more sensitive, and can see the trends easily.
+ */
+@InterfaceAudience.Public
+public class ExponentialMovingAverage extends WindowMovingAverage {
+ private double alpha;
+ private double previousAverage;
+ private double currentAverage;
+
+ public ExponentialMovingAverage() {
+ this(DEFAULT_SIZE);
+ }
+
+ public ExponentialMovingAverage(double alpha) {
+ this(DEFAULT_SIZE, alpha);
+ }
+
+ public ExponentialMovingAverage(int size) {
+ this(size, (double) 2 / (1 + size));
+ }
+
+ public ExponentialMovingAverage(int size, double alpha) {
+ super(size);
+ this.previousAverage = -1.0;
+ this.currentAverage = 0.0;
+ this.alpha = alpha;
+ }
+
+ @Override
+ public void updateMostRecentTime(long elapsed) {
+ if (!enoughStatistics()) {
+ previousAverage = super.getAverageTime();
+ super.updateMostRecentTime(elapsed);
+ if (!enoughStatistics()) {
+ return;
+ }
+ }
+ // CurrentEMA = α * currentValue + (1 - α) * previousEMA =>
+ // CurrentEMA = (currentValue - previousEMA) * α + previousEMA
+ // This will reduce multiplication.
+ currentAverage = (elapsed - previousAverage) * alpha + previousAverage;
+ previousAverage = currentAverage;
+ }
+
+ @Override
+ public double getAverageTime() {
+ if (!enoughStatistics()) {
+ return super.getAverageTime();
+ }
+ return currentAverage;
+ }
+
+ double getPrevious() {
+ return previousAverage;
+ }
+}
diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/MovingAverage.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/MovingAverage.java
new file mode 100644
index 0000000..7687915
--- /dev/null
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/MovingAverage.java
@@ -0,0 +1,81 @@
+/*
+ * 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.hbase.util;
+
+import org.apache.yetus.audience.InterfaceAudience;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * The purpose of introduction of {@link MovingAverage} mainly is to measure execution time of a
+ * specific method, which can help us to know its performance fluctuation in response to different
+ * machine states or situations, better case, then to act accordingly.
+ * <br>
+ * In different situation, different {@link MovingAverage} algorithm can be used based on needs.
+ */
+@InterfaceAudience.Public
+public abstract class MovingAverage<T> {
+ private final static Logger LOG = LoggerFactory.getLogger(MovingAverage.class);
+
+ /**
+ * Mark start time of an execution.
+ * @return time in ns.
+ */
+ protected long start() {
+ return System.nanoTime();
+ }
+
+ /**
+ * Mark end time of an execution, and return its interval.
+ * @param startTime start time of an execution
+ * @return elapsed time
+ */
+ protected long stop(long startTime) {
+ return System.nanoTime() - startTime;
+ }
+
+ /**
+ * Measure elapsed time of a measurable method.
+ * @param measurable method implements {@link TimeMeasurable}
+ * @return T it refers to the original return type of the measurable method
+ */
+ public T measure(TimeMeasurable<T> measurable) {
+ long startTime = start();
+ LOG.debug("Start to measure at: {} ns.", startTime);
+ // Here may throw exceptions which should be taken care by caller, not here.
+ // If exception occurs, this time wouldn't count.
+ T result = measurable.measure();
+ long elapsed = stop(startTime);
+ LOG.debug("Elapse: {} ns.", elapsed);
+ updateMostRecentTime(elapsed);
+ return result;
+ }
+
+ /**
+ * Update the most recent data.
+ * @param elapsed elapsed time of the most recent measurement
+ */
+ protected abstract void updateMostRecentTime(long elapsed);
+
+ /**
+ * Get average execution time of the measured method.
+ * @return average time in ns
+ */
+ public abstract double getAverageTime();
+}
diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/SimpleMovingAverage.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/SimpleMovingAverage.java
new file mode 100644
index 0000000..058c9f6
--- /dev/null
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/SimpleMovingAverage.java
@@ -0,0 +1,45 @@
+/*
+ * 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.hbase.util;
+
+import org.apache.yetus.audience.InterfaceAudience;
+
+/**
+ * SMA measure the overall average execution time of a specific method.
+ */
+@InterfaceAudience.Public
+public class SimpleMovingAverage extends MovingAverage {
+ private double averageTime = 0.0;
+ protected long count = 0;
+
+ public SimpleMovingAverage() {
+ this.averageTime = 0.0;
+ this.count = 0;
+ }
+
+ @Override
+ public void updateMostRecentTime(long elapsed) {
+ averageTime += (elapsed - averageTime) / (++count);
+ }
+
+ @Override
+ public double getAverageTime() {
+ return averageTime;
+ }
+}
diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/TimeMeasurable.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/TimeMeasurable.java
new file mode 100644
index 0000000..111093d
--- /dev/null
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/TimeMeasurable.java
@@ -0,0 +1,35 @@
+/*
+ * 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.hbase.util;
+
+import org.apache.yetus.audience.InterfaceAudience;
+
+/**
+ * Methods that implement this interface can be measured elapsed time.
+ * It works together with {@link MovingAverage} to take effect.
+ */
+@InterfaceAudience.Public
+public interface TimeMeasurable<T> {
+
+ /**
+ * Measure elapsed time.
+ * @return T
+ */
+ T measure();
+}
diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/WeightedMovingAverage.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/WeightedMovingAverage.java
new file mode 100644
index 0000000..33aa5698
--- /dev/null
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/WeightedMovingAverage.java
@@ -0,0 +1,65 @@
+/*
+ * 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.hbase.util;
+
+import org.apache.yetus.audience.InterfaceAudience;
+
+/**
+ * Different from SMA {@link SimpleMovingAverage}, WeightedMovingAverage gives each data different
+ * weight. And it is based on {@link WindowMovingAverage}, such that it only focus on the last N.
+ */
+@InterfaceAudience.Public
+public class WeightedMovingAverage extends WindowMovingAverage {
+ private int[] coefficient;
+ private int denominator;
+
+ public WeightedMovingAverage() {
+ this(DEFAULT_SIZE);
+ }
+
+ public WeightedMovingAverage(int size) {
+ super(size);
+ int length = getNumberOfStatistics();
+ denominator = length * (length + 1) / 2;
+ coefficient = new int[length];
+ // E.g. default size is 5, coefficient should be [1, 2, 3, 4, 5]
+ for (int i = 0; i < length; i++) {
+ coefficient[i] = i + 1;
+ }
+ }
+
+ @Override
+ public double getAverageTime() {
+ if (!enoughStatistics()) {
+ return super.getAverageTime();
+ }
+ // only we get enough statistics, then start WMA.
+ double average = 0.0;
+ int coIndex = 0;
+ int length = getNumberOfStatistics();
+ // tmIndex, it points to the oldest data.
+ for (int tmIndex = (getMostRecentPosistion() + 1) % length;
+ coIndex < length;
+ coIndex++, tmIndex = (++tmIndex) % length) {
+ // start the multiplication from oldest to newest
+ average += coefficient[coIndex] * getStatisticsAtIndex(tmIndex);
+ }
+ return average / denominator;
+ }
+}
diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/WindowMovingAverage.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/WindowMovingAverage.java
new file mode 100644
index 0000000..fbfc73b
--- /dev/null
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/WindowMovingAverage.java
@@ -0,0 +1,118 @@
+/*
+ * 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.hbase.util;
+
+import org.apache.yetus.audience.InterfaceAudience;
+
+/**
+ * Instead of calculate a whole time average, this class focus on the last N.
+ * The last N is stored in a circle array.
+ */
+@InterfaceAudience.Public
+public class WindowMovingAverage extends MovingAverage {
+ protected final static int DEFAULT_SIZE = 5;
+
+ // The last n statistics.
+ protected long[] lastN;
+ // The index of the most recent statistics.
+ protected int mostRecent;
+ // If it travels a round.
+ protected boolean oneRound;
+
+ public WindowMovingAverage() {
+ this(DEFAULT_SIZE);
+ }
+
+ public WindowMovingAverage(int size) {
+ this.lastN = new long[size <= 0 ? DEFAULT_SIZE : size];
+ this.mostRecent = -1;
+ this.oneRound = false;
+ }
+
+ @Override
+ protected void updateMostRecentTime(long elapsed) {
+ int index = moveForwardMostRecentPosistion();
+ lastN[index] = elapsed;
+ }
+
+ @Override
+ public double getAverageTime() {
+ return enoughStatistics() ?
+ (double) sum(getNumberOfStatistics()) / getNumberOfStatistics() :
+ (double) sum(getMostRecentPosistion() + 1) / (getMostRecentPosistion() + 1);
+ }
+
+ /**
+ * Check if there are enough statistics.
+ * @return true if lastN is full
+ */
+ protected boolean enoughStatistics() {
+ return oneRound;
+ }
+
+ /**
+ * @return number of statistics
+ */
+ protected int getNumberOfStatistics() {
+ return lastN.length;
+ }
+
+ /**
+ * Get statistics at index.
+ * @param index index of bar
+ * @return statistics
+ */
+ protected long getStatisticsAtIndex(int index) {
+ if (index < 0 || index >= getNumberOfStatistics()) {
+ // This case should not happen, but a prudent check.
+ throw new IndexOutOfBoundsException();
+ }
+ return lastN[index];
+ }
+
+ /**
+ * @return index of most recent
+ */
+ protected int getMostRecentPosistion() {
+ return mostRecent;
+ }
+
+ /**
+ * Move forward the most recent index.
+ * @return the most recent index
+ */
+ protected int moveForwardMostRecentPosistion() {
+ int index = ++mostRecent;
+ if (!oneRound && index == getNumberOfStatistics()) {
+ // Back to the head of the lastN, from now on will
+ // start to evict oldest value.
+ oneRound = true;
+ }
+ mostRecent = index % getNumberOfStatistics();
+ return mostRecent;
+ }
+
+ private long sum(int bound) {
+ long sum = 0;
+ for (int i = 0; i < bound; i++) {
+ sum += getStatisticsAtIndex(i);
+ }
+ return sum;
+ }
+}
diff --git a/hbase-common/src/test/java/org/apache/hadoop/hbase/util/TestMovingAverage.java b/hbase-common/src/test/java/org/apache/hadoop/hbase/util/TestMovingAverage.java
new file mode 100644
index 0000000..990cacd
--- /dev/null
+++ b/hbase-common/src/test/java/org/apache/hadoop/hbase/util/TestMovingAverage.java
@@ -0,0 +1,152 @@
+/**
+ * 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.hbase.util;
+
+import org.apache.hadoop.hbase.HBaseClassTestRule;
+import org.apache.hadoop.hbase.testclassification.SmallTests;
+import org.junit.Assert;
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+@Category(SmallTests.class)
+public class TestMovingAverage {
+
+ @ClassRule
+ public static final HBaseClassTestRule CLASS_RULE =
+ HBaseClassTestRule.forClass(TestMovingAverage.class);
+
+ private long[] data = {1, 12, 13, 24, 25, 26, 37, 38, 39, 40};
+ private double delta = 0.1;
+
+ @Test
+ public void testSimpleMovingAverage() throws Exception {
+ MovingAverage<?> algorithm = new SimpleMovingAverage();
+ int index = 0;
+ // [1, 12, 13, 24]
+ int bound = 4;
+ for (; index < bound; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(12.5, algorithm.getAverageTime(), delta);
+ // [1, 12, 13, 24, 25]
+ bound = 5;
+ for (; index < bound; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(15.0, algorithm.getAverageTime(), delta);
+ // [1, 12, 13, 24, 25, 26, 37, 38]
+ bound = 8;
+ for (; index < bound; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(22.0, algorithm.getAverageTime(), delta);
+ // [1, 12, 13, 24, 25, 26, 37, 38, 39, 40]
+ for (; index < data.length; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(25.5, algorithm.getAverageTime(), delta);
+ }
+
+ @Test
+ public void testWindowMovingAverage() throws Exception {
+ // Default size is 5.
+ MovingAverage<?> algorithm = new WindowMovingAverage();
+ int index = 0;
+ // [1, 12, 13, 24]
+ int bound = 4;
+ for (; index < bound; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(12.5, algorithm.getAverageTime(), delta);
+ // [1, 12, 13, 24, 25]
+ bound = 5;
+ for (; index < bound; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(15.0, algorithm.getAverageTime(), delta);
+ // [24, 25, 26, 37, 38]
+ bound = 8;
+ for (; index < bound; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(30.0, algorithm.getAverageTime(), delta);
+ // [26, 37, 38, 39, 40]
+ for (; index < data.length; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(36.0, algorithm.getAverageTime(), delta);
+ }
+
+ @Test
+ public void testWeightedMovingAverage() throws Exception {
+ // Default size is 5.
+ MovingAverage<?> algorithm = new WeightedMovingAverage();
+ int index = 0;
+ // [1, 12, 13, 24]
+ int bound = 4;
+ for (; index < bound; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(12.5, algorithm.getAverageTime(), delta);
+ // [1, 12, 13, 24, 25]
+ bound = 5;
+ for (; index < bound; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(15.0, algorithm.getAverageTime(), delta);
+ // [24, 25, 26, 37, 38]
+ bound = 8;
+ for (; index < bound; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(32.67, algorithm.getAverageTime(), delta);
+ // [26, 37, 38, 39, 40]
+ for (; index < data.length; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(38.0, algorithm.getAverageTime(), delta);
+ }
+
+ @Test
+ public void testExponentialMovingAverage() throws Exception {
+ // [1, 12, 13, 24, 25, 26, 37, 38, 39, 40]
+ MovingAverage<?> algorithm = new ExponentialMovingAverage();
+ int index = 0;
+ int bound = 5;
+ for (; index < bound; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(15.0, algorithm.getAverageTime(), delta);
+ bound = 6;
+ for (; index < bound; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(18.67, algorithm.getAverageTime(), delta);
+ bound = 8;
+ for (; index < bound; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(29.16, algorithm.getAverageTime(), delta);
+ for (; index < data.length; index++) {
+ algorithm.updateMostRecentTime(data[index]);
+ }
+ Assert.assertEquals(34.97, algorithm.getAverageTime(), delta);
+ }
+}