YARN-146. Add unit tests for computing fair share in the fair scheduler. Contributed by Sandy Ryza.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1396972 13f79535-47bb-0310-9956-ffa450edef68

hadoop-yarn-project/CHANGES.txt

@@ -58,6 +58,9 @@ Release 2.0.3-alpha - Unreleased
     YARN-94. Modify DistributedShell to point to main-class by default, clean up
     the help message, and hard-code the AM class. (Hitesh Shah via vinodkv)
 
+    YARN-146. Add unit tests for computing fair share in the fair scheduler.
+    (Sandy Ryza via tomwhite)
+
   OPTIMIZATIONS
 
   BUG FIXES

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FakeSchedulable.java

@@ -0,0 +1,115 @@
+/**
+ * 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.yarn.server.resourcemanager.scheduler.fair;
+
+import org.apache.hadoop.yarn.api.records.Priority;
+import org.apache.hadoop.yarn.api.records.Resource;
+import org.apache.hadoop.yarn.server.resourcemanager.resource.Resources;
+import org.apache.hadoop.yarn.util.Records;
+
+/**
+ * Dummy implementation of Schedulable for unit testing.
+ */
+public class FakeSchedulable extends Schedulable {
+  private Resource demand;
+  private Resource usage;
+  private Resource minShare;
+  private double weight;
+  private Priority priority;
+  private long startTime;
+  
+  public FakeSchedulable() {
+    this(0, 0, 1, 0, 0, 0);
+  }
+  
+  public FakeSchedulable(int demand) {
+    this(demand, 0, 1, 0, 0, 0);
+  }
+  
+  public FakeSchedulable(int demand, int minShare) {
+    this(demand, minShare, 1, 0, 0, 0);
+  }
+  
+  public FakeSchedulable(int demand, int minShare, double weight) {
+    this(demand, minShare, weight, 0, 0, 0);
+  }
+  
+  public FakeSchedulable(int demand, int minShare, double weight, int fairShare, int usage,
+      long startTime) {
+    this(Resources.createResource(demand), Resources.createResource(minShare), weight, 
+        Resources.createResource(fairShare), Resources.createResource(usage), startTime);
+  }
+  
+  public FakeSchedulable(Resource demand, Resource minShare, double weight, Resource fairShare,
+      Resource usage, long startTime) {
+    this.demand = demand;
+    this.minShare = minShare;
+    this.weight = weight;
+    setFairShare(fairShare);
+    this.usage = usage;
+    this.priority = Records.newRecord(Priority.class);
+    this.startTime = startTime;
+  }
+  
+  @Override
+  public Resource assignContainer(FSSchedulerNode node, boolean reserved) {
+    return null;
+  }
+
+  @Override
+  public Resource getDemand() {
+    return demand;
+  }
+
+  @Override
+  public String getName() {
+    return "FakeSchedulable" + this.hashCode();
+  }
+
+  @Override
+  public Priority getPriority() {
+    return priority;
+  }
+
+  @Override
+  public Resource getResourceUsage() {
+    return usage;
+  }
+
+  @Override
+  public long getStartTime() {
+    return startTime;
+  }
+  
+  @Override
+  public double getWeight() {
+    return weight;
+  }
+  
+  @Override
+  public Resource getMinShare() {
+    return minShare;
+  }
+
+  @Override
+  public void redistributeShare() {}
+
+  @Override
+  public void updateDemand() {}
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/TestComputeFairShares.java

@@ -0,0 +1,184 @@
+/**
+ * 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.yarn.server.resourcemanager.scheduler.fair;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import junit.framework.Assert;
+
+import org.apache.hadoop.yarn.server.resourcemanager.resource.Resources;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Exercise the computeFairShares method in SchedulingAlgorithms.
+ */
+public class TestComputeFairShares {
+  private List<Schedulable> scheds;
+  
+  @Before
+  public void setUp() throws Exception {
+    scheds = new ArrayList<Schedulable>();
+  }
+  
+  /** 
+   * Basic test - pools with different demands that are all higher than their
+   * fair share (of 10 slots) should each get their fair share.
+   */
+  @Test
+  public void testEqualSharing() {
+    scheds.add(new FakeSchedulable(100));
+    scheds.add(new FakeSchedulable(50));
+    scheds.add(new FakeSchedulable(30));
+    scheds.add(new FakeSchedulable(20));
+    SchedulingAlgorithms.computeFairShares(scheds, Resources.createResource(40));
+    verifyShares(10, 10, 10, 10);
+  }
+  
+  /**
+   * In this test, pool 4 has a smaller demand than the 40 / 4 = 10 slots that
+   * it would be assigned with equal sharing. It should only get the 3 slots
+   * it demands. The other pools must then split the remaining 37 slots, but
+   * pool 3, with 11 slots demanded, is now below its share of 37/3 ~= 12.3,
+   * so it only gets 11 slots. Pools 1 and 2 split the rest and get 13 each. 
+   */
+  @Test
+  public void testLowDemands() {
+    scheds.add(new FakeSchedulable(100));
+    scheds.add(new FakeSchedulable(50));
+    scheds.add(new FakeSchedulable(11));
+    scheds.add(new FakeSchedulable(3));
+    SchedulingAlgorithms.computeFairShares(scheds, Resources.createResource(40));
+    verifyShares(13, 13, 11, 3);
+  }
+  
+  /**
+   * In this test, some pools have minimum shares set. Pool 1 has a min share
+   * of 20 so it gets 20 slots. Pool 2 also has a min share of 20, but its
+   * demand is only 10 so it can only get 10 slots. The remaining pools have
+   * 10 slots to split between them. Pool 4 gets 3 slots because its demand is
+   * only 3, and pool 3 gets the remaining 7 slots. Pool 4 also had a min share
+   * of 2 slots but this should not affect the outcome.
+   */
+  @Test
+  public void testMinShares() {
+    scheds.add(new FakeSchedulable(100, 20));
+    scheds.add(new FakeSchedulable(10, 20));
+    scheds.add(new FakeSchedulable(10, 0));
+    scheds.add(new FakeSchedulable(3, 2));
+    SchedulingAlgorithms.computeFairShares(scheds, Resources.createResource(40));
+    verifyShares(20, 10, 7, 3);
+  }
+  
+  /**
+   * Basic test for weighted shares with no minimum shares and no low demands.
+   * Each pool should get slots in proportion to its weight.
+   */
+  @Test
+  public void testWeightedSharing() {
+    scheds.add(new FakeSchedulable(100, 0, 2.0));
+    scheds.add(new FakeSchedulable(50,  0, 1.0));
+    scheds.add(new FakeSchedulable(30,  0, 1.0));
+    scheds.add(new FakeSchedulable(20,  0, 0.5));
+    SchedulingAlgorithms.computeFairShares(scheds, Resources.createResource(45));
+    verifyShares(20, 10, 10, 5);
+  }
+
+  /**
+   * Weighted sharing test where pools 1 and 2 are now given lower demands than
+   * above. Pool 1 stops at 10 slots, leaving 35. If the remaining pools split
+   * this into a 1:1:0.5 ratio, they would get 14:14:7 slots respectively, but
+   * pool 2's demand is only 11, so it only gets 11. The remaining 2 pools split
+   * the 24 slots left into a 1:0.5 ratio, getting 16 and 8 slots respectively.
+   */
+  @Test
+  public void testWeightedSharingWithLowDemands() {
+    scheds.add(new FakeSchedulable(10, 0, 2.0));
+    scheds.add(new FakeSchedulable(11, 0, 1.0));
+    scheds.add(new FakeSchedulable(30, 0, 1.0));
+    scheds.add(new FakeSchedulable(20, 0, 0.5));
+    SchedulingAlgorithms.computeFairShares(scheds, Resources.createResource(45));
+    verifyShares(10, 11, 16, 8);
+  }
+
+  /**
+   * Weighted fair sharing test with min shares. As in the min share test above,
+   * pool 1 has a min share greater than its demand so it only gets its demand.
+   * Pool 3 has a min share of 15 even though its weight is very small, so it
+   * gets 15 slots. The remaining pools share the remaining 20 slots equally,
+   * getting 10 each. Pool 3's min share of 5 slots doesn't affect this.
+   */
+  @Test
+  public void testWeightedSharingWithMinShares() {
+    scheds.add(new FakeSchedulable(10, 20, 2.0));
+    scheds.add(new FakeSchedulable(11, 0, 1.0));
+    scheds.add(new FakeSchedulable(30, 5, 1.0));
+    scheds.add(new FakeSchedulable(20, 15, 0.5));
+    SchedulingAlgorithms.computeFairShares(scheds, Resources.createResource(45));
+    verifyShares(10, 10, 10, 15);
+  }
+
+  /**
+   * Test that shares are computed accurately even when the number of slots is
+   * very large.
+   */
+  @Test
+  public void testLargeShares() {
+    int million = 1000 * 1000;
+    scheds.add(new FakeSchedulable(100 * million));
+    scheds.add(new FakeSchedulable(50 * million));
+    scheds.add(new FakeSchedulable(30 * million));
+    scheds.add(new FakeSchedulable(20 * million));
+    SchedulingAlgorithms.computeFairShares(scheds, Resources.createResource(40 * million));
+    verifyShares(10 * million, 10 * million, 10 * million, 10 * million);
+  }
+
+  /**
+   * Test that having a pool with 0 demand doesn't confuse the algorithm.
+   */
+  @Test
+  public void testZeroDemand() {
+    scheds.add(new FakeSchedulable(100));
+    scheds.add(new FakeSchedulable(50));
+    scheds.add(new FakeSchedulable(30));
+    scheds.add(new FakeSchedulable(0));
+    SchedulingAlgorithms.computeFairShares(scheds, Resources.createResource(30));
+    verifyShares(10, 10, 10, 0);
+  }
+  
+  /**
+   * Test that being called on an empty list doesn't confuse the algorithm.
+   */
+  @Test
+  public void testEmptyList() {
+    SchedulingAlgorithms.computeFairShares(scheds, Resources.createResource(40));
+    verifyShares();
+  }
+  
+  /**
+   * Check that a given list of shares have been assigned to this.scheds.
+   */
+  private void verifyShares(double... shares) {
+    Assert.assertEquals(scheds.size(), shares.length);
+    for (int i = 0; i < shares.length; i++) {
+      Assert.assertEquals(shares[i], scheds.get(i).getFairShare().getMemory(), 0.01);
+    }
+  }
+}