/**
* 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.mapred;
import java.util.ArrayList;
import java.util.List;
import junit.framework.TestCase;
/**
* Exercise the computeFairShares method in SchedulingAlgorithms.
*/
public class TestComputeFairShares extends TestCase {
private List<Schedulable> scheds;
@Override
protected 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.
*/
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, 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.
*/
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, 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.
*/
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, 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.
*/
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, 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.
*/
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, 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.
*/
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, 45);
verifyShares(10, 10, 10, 15);
}
/**
* Test that shares are computed accurately even when there are many more
* frameworks than available slots.
*/
public void testSmallShares() {
scheds.add(new FakeSchedulable(10));
scheds.add(new FakeSchedulable(5));
scheds.add(new FakeSchedulable(3));
scheds.add(new FakeSchedulable(2));
SchedulingAlgorithms.computeFairShares(scheds, 1);
verifyShares(0.25, 0.25, 0.25, 0.25);
}
/**
* Test that shares are computed accurately even when the number of slots is
* very large.
*/
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, 40 * million);
verifyShares(10 * million, 10 * million, 10 * million, 10 * million);
}
/**
* Test that having a pool with 0 demand doesn't confuse the algorithm.
*/
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, 30);
verifyShares(10, 10, 10, 0);
}
/**
* Test that being called on an empty list doesn't confuse the algorithm.
*/
public void testEmptyList() {
SchedulingAlgorithms.computeFairShares(scheds, 40);
verifyShares();
}
/**
* Check that a given list of shares have been assigned to this.scheds.
*/
private void verifyShares(double... shares) {
assertEquals(scheds.size(), shares.length);
for (int i = 0; i < shares.length; i++) {
assertEquals(shares[i], scheds.get(i).getFairShare(), 0.01);
}
}
}