TestComputeFairShares.java
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* 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 static org.junit.jupiter.api.Assertions.assertEquals;
import java.util.ArrayList;
import java.util.List;
import org.apache.hadoop.yarn.api.records.ResourceInformation;
import org.apache.hadoop.yarn.util.resource.Resources;
import org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.policies.ComputeFairShares;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
/**
* Exercise the computeFairShares method in SchedulingAlgorithms.
*/
public class TestComputeFairShares {
private List<Schedulable> scheds;
@BeforeEach
public void setUp() throws Exception {
scheds = new ArrayList<>();
}
/**
* 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());
scheds.add(new FakeSchedulable());
scheds.add(new FakeSchedulable());
scheds.add(new FakeSchedulable());
ComputeFairShares.computeShares(scheds,
Resources.createResource(40), ResourceInformation.MEMORY_MB.getName());
verifyMemoryShares(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 testLowMaxShares() {
scheds.add(new FakeSchedulable(0, 100));
scheds.add(new FakeSchedulable(0, 50));
scheds.add(new FakeSchedulable(0, 11));
scheds.add(new FakeSchedulable(0, 3));
ComputeFairShares.computeShares(scheds,
Resources.createResource(40), ResourceInformation.MEMORY_MB.getName());
verifyMemoryShares(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(20));
scheds.add(new FakeSchedulable(18));
scheds.add(new FakeSchedulable(0));
scheds.add(new FakeSchedulable(2));
ComputeFairShares.computeShares(scheds,
Resources.createResource(40), ResourceInformation.MEMORY_MB.getName());
verifyMemoryShares(20, 18, 0, 2);
}
/**
* 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(0, 2.0f));
scheds.add(new FakeSchedulable(0, 1.0f));
scheds.add(new FakeSchedulable(0, 1.0f));
scheds.add(new FakeSchedulable(0, 0.5f));
ComputeFairShares.computeShares(scheds,
Resources.createResource(45), ResourceInformation.MEMORY_MB.getName());
verifyMemoryShares(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 testWeightedSharingWithMaxShares() {
scheds.add(new FakeSchedulable(0, 10, 2.0f));
scheds.add(new FakeSchedulable(0, 11, 1.0f));
scheds.add(new FakeSchedulable(0, 30, 1.0f));
scheds.add(new FakeSchedulable(0, 20, 0.5f));
ComputeFairShares.computeShares(scheds,
Resources.createResource(45), ResourceInformation.MEMORY_MB.getName());
verifyMemoryShares(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(20, 2.0f));
scheds.add(new FakeSchedulable(0, 1.0f));
scheds.add(new FakeSchedulable(5, 1.0f));
scheds.add(new FakeSchedulable(15, 0.5f));
ComputeFairShares.computeShares(scheds,
Resources.createResource(45), ResourceInformation.MEMORY_MB.getName());
verifyMemoryShares(20, 5, 5, 15);
}
/**
* Test that shares are computed accurately even when the number of
* resources is very large.
* Test adapted to accommodate long values for resources.
*/
@Test
public void testLargeShares() {
long giga = 1000L * 1000L * 1000L * 4L;
scheds.add(new FakeSchedulable(0L, giga));
scheds.add(new FakeSchedulable(0L, giga));
scheds.add(new FakeSchedulable(0L, giga));
scheds.add(new FakeSchedulable(0L, giga));
ComputeFairShares.computeShares(scheds,
Resources.createResource(4 * giga),
ResourceInformation.MEMORY_MB.getName());
verifyMemoryShares(giga, giga, giga, giga);
}
/**
* Test overflow in the resources taken and upper bound.
*/
@Test
public void testLargeMinimums() {
long giga = 1000L * 1000L * 1000L * 4L;
scheds.add(new FakeSchedulable(Long.MAX_VALUE, Long.MAX_VALUE));
scheds.add(new FakeSchedulable(giga, giga));
ComputeFairShares.computeShares(scheds,
Resources.createResource(4 * giga),
ResourceInformation.MEMORY_MB.getName());
verifyMemoryShares(Long.MAX_VALUE, giga);
}
/**
* Test overflow in the upper bound calculation for the binary search.
*/
@Test
public void testOverflowMaxShare() {
long giga = 1000L * 1000L * 1000L;
scheds.add(new FakeSchedulable(0L, giga));
scheds.add(new FakeSchedulable(0L, Long.MAX_VALUE));
ComputeFairShares.computeShares(scheds,
Resources.createResource(2 * giga),
ResourceInformation.MEMORY_MB.getName());
verifyMemoryShares(giga, giga);
}
/**
* Test overflow in the fixed share calculations. The 3th schedulable should
* not get any share as all resources are taken by the handleFixedShare()
* call.
* With the overflow it looked like there were more resources available then
* there really are.
* The values in the test might not be "real" but they show the overflow.
*/
@Test
public void testOverflowFixedShare() {
long giga = 1000L * 1000L * 1000L;
long minValue = Long.MAX_VALUE - 1L;
scheds.add(new FakeSchedulable(giga, giga, 0));
scheds.add(new FakeSchedulable(minValue, Long.MAX_VALUE, 0));
scheds.add(new FakeSchedulable(0L, giga));
ComputeFairShares.computeShares(scheds,
Resources.createResource(1000L),
ResourceInformation.MEMORY_MB.getName());
verifyMemoryShares(giga, minValue, 0);
}
/**
* Test that being called on an empty list doesn't confuse the algorithm.
*/
@Test
public void testEmptyList() {
ComputeFairShares.computeShares(scheds,
Resources.createResource(40), ResourceInformation.MEMORY_MB.getName());
verifyMemoryShares();
}
/**
* Test that CPU works as well as memory.
*/
@Test
public void testCPU() {
scheds.add(new FakeSchedulable(Resources.createResource(0, 20), 2.0f));
scheds.add(new FakeSchedulable(Resources.createResource(0, 0), 1.0f));
scheds.add(new FakeSchedulable(Resources.createResource(0, 5), 1.0f));
scheds.add(new FakeSchedulable(Resources.createResource(0, 15), 0.5f));
ComputeFairShares.computeShares(scheds,
Resources.createResource(0, 45), ResourceInformation.VCORES.getName());
verifyCPUShares(20, 5, 5, 15);
}
/**
* Check that a given list of shares have been assigned to this.scheds.
*/
private void verifyMemoryShares(long... shares) {
assertEquals(scheds.size(), shares.length,
"Number of shares and schedulables are not consistent");
for (int i = 0; i < shares.length; i++) {
assertEquals(shares[i], scheds.get(i).getFairShare().getMemorySize(),
"Expected share number " + i + " in list wrong");
}
}
/**
* Check that a given list of shares have been assigned to this.scheds.
*/
private void verifyCPUShares(int... shares) {
assertEquals(scheds.size(), shares.length,
"Number of shares and schedulables are not consistent");
for (int i = 0; i < shares.length; i++) {
assertEquals(shares[i], scheds.get(i).getFairShare().getVirtualCores(),
"Expected share number " + i + " in list wrong");
}
}
}