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https://issues.apache.org/jira/browse/FLINK-10431?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16660893#comment-16660893
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ASF GitHub Bot commented on FLINK-10431:
----------------------------------------
tillrohrmann commented on a change in pull request #6898: [FLINK-10431]
Extraction of scheduling-related code from SlotPool into preliminary Scheduler
URL: https://github.com/apache/flink/pull/6898#discussion_r227453190
##########
File path:
flink-runtime/src/main/java/org/apache/flink/runtime/jobmaster/slotpool/LocationPreferenceSlotSelection.java
##########
@@ -0,0 +1,111 @@
+/*
+ * 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.flink.runtime.jobmaster.slotpool;
+
+import org.apache.flink.runtime.clusterframework.types.ResourceID;
+import org.apache.flink.runtime.clusterframework.types.ResourceProfile;
+import org.apache.flink.runtime.clusterframework.types.SlotProfile;
+import org.apache.flink.runtime.jobmanager.scheduler.Locality;
+import org.apache.flink.runtime.jobmaster.SlotInfo;
+import org.apache.flink.runtime.taskmanager.TaskManagerLocation;
+
+import javax.annotation.Nonnull;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.BiFunction;
+
+/**
+ * This class implements a {@link SlotSelectionStrategy} that is based on
location preference hints.
+ */
+public class LocationPreferenceSlotSelection implements SlotSelectionStrategy {
+
+ public static final LocationPreferenceSlotSelection INSTANCE = new
LocationPreferenceSlotSelection();
+
+ private LocationPreferenceSlotSelection() {
+ }
+
+ /**
+ * Calculates the candidate's locality score.
+ */
+ private static final BiFunction<Integer, Integer, Integer>
LOCALITY_EVALUATION_FUNCTION =
+ (localWeigh, hostLocalWeigh) -> localWeigh * 10 +
hostLocalWeigh;
+
+ @Nonnull
+ @Override
+ public SlotInfoAndLocality selectBestSlotForProfile(
+ @Nonnull List<SlotInfo> availableSlots,
+ @Nonnull SlotProfile slotProfile) {
+
+ Collection<TaskManagerLocation> locationPreferences =
slotProfile.getPreferredLocations();
+
+ if (availableSlots.isEmpty()) {
+ return SlotInfoAndLocality.of(null, Locality.UNKNOWN);
+ }
+
+ final ResourceProfile resourceProfile =
slotProfile.getResourceProfile();
+
+ // if we have no location preferences, we can only filter by
the additional requirements.
+ if (locationPreferences.isEmpty()) {
+ for (SlotInfo candidate : availableSlots) {
+ if
(candidate.getResourceProfile().isMatching(resourceProfile)) {
+ return
SlotInfoAndLocality.of(candidate, Locality.UNCONSTRAINED);
+ }
+ }
+ return SlotInfoAndLocality.of(null, Locality.UNKNOWN);
+ }
+
+ // we build up two indexes, one for resource id and one for
host names of the preferred locations.
+ final Map<ResourceID, Integer> preferredResourceIDs = new
HashMap<>(locationPreferences.size());
+ final Map<String, Integer> preferredFQHostNames = new
HashMap<>(locationPreferences.size());
+
+ for (TaskManagerLocation locationPreference :
locationPreferences) {
+
preferredResourceIDs.merge(locationPreference.getResourceID(), 1, Integer::sum);
+
preferredFQHostNames.merge(locationPreference.getFQDNHostname(), 1,
Integer::sum);
+ }
+
+ SlotInfo bestCandidate = null;
+ Locality bestCandidateLocality = Locality.UNKNOWN;
+ int bestCandidateScore = Integer.MIN_VALUE;
+
+ for (SlotInfo candidate : availableSlots) {
+
+ if
(candidate.getResourceProfile().isMatching(resourceProfile)) {
+
+ // this gets candidate is local-weigh
+ Integer localWeigh =
preferredResourceIDs.getOrDefault(candidate.getTaskManagerLocation().getResourceID(),
0);
+
+ // this gets candidate is host-local-weigh
+ Integer hostLocalWeigh =
preferredFQHostNames.getOrDefault(candidate.getTaskManagerLocation().getFQDNHostname(),
0);
+
+ int candidateScore =
LOCALITY_EVALUATION_FUNCTION.apply(localWeigh, hostLocalWeigh);
+ if (candidateScore > bestCandidateScore) {
+ bestCandidateScore = candidateScore;
+ bestCandidate = candidate;
+ bestCandidateLocality = localWeigh > 0
? Locality.LOCAL : hostLocalWeigh > 0 ? Locality.HOST_LOCAL :
Locality.NON_LOCAL;
+ }
+ }
+ }
+
+ // at the end of the iteration, we return the candidate with
best possible locality or null.
+ return SlotInfoAndLocality.of(bestCandidate,
bestCandidateLocality);
Review comment:
This block could be separate method as well, e.g.
`selectBestSlotByPreferredLocations`
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> Extract scheduling-related code from SlotPool
> ---------------------------------------------
>
> Key: FLINK-10431
> URL: https://issues.apache.org/jira/browse/FLINK-10431
> Project: Flink
> Issue Type: Sub-task
> Components: Distributed Coordination
> Affects Versions: 1.7.0
> Reporter: Stefan Richter
> Assignee: Stefan Richter
> Priority: Major
> Labels: pull-request-available
>
> The other half of the current scheduling logic is the management of slot
> sharing and is located in the SlotPool. We need to extract this logic into
> our new Scheduler component from the previous step. This leaves us with a
> simpler SlotPool that mainly cares about obtaining, holding, and releasing
> slots in interaction with a ResourceManager. The new Scheduler can now
> identify slot sharing groups and interacts with the SlotPool.
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