davidradl commented on code in PR #27189: URL: https://github.com/apache/flink/pull/27189#discussion_r2490928141
########## flink-runtime/src/main/java/org/apache/flink/runtime/jobmaster/slotpool/ResourceRequestPreMappings.java: ########## @@ -0,0 +1,415 @@ +/* + * 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.annotation.VisibleForTesting; +import org.apache.flink.runtime.clusterframework.types.ResourceProfile; +import org.apache.flink.util.CollectionUtil; +import org.apache.flink.util.Preconditions; + +import java.util.Collection; +import java.util.Collections; +import java.util.HashMap; +import java.util.Map; +import java.util.Optional; +import java.util.stream.Collectors; + +/** + * This class is designed to handle the pre-matching of resource requests in the context of balanced + * task scheduling for streaming jobs. During the batch allocation of resources, where resource + * requests are allocated in a single, non-interleaved operation, it is impossible to make immediate + * individual adjustments to unmatched resource requests. This may lead to situations where not all + * resource requests can be successfully fulfilled. For example: + * + * <pre> + * resource requests: + * - resource request-1: ResourceProfile-1(UNKNOWN) + * - resource request-2: ResourceProfile-2(cpu=2 core, memory=2G) + * + * available slots: + * - slot-a: ResourceProfile-a(cpu=1 core, memory=1G) + * - slot-b: ResourceProfile-b(cpu=2 core, memory=2G) + * </pre> + * + * When the strategy {@link TasksBalancedRequestSlotMatchingStrategy} performs resource allocation, + * the following matching mapping might occur, preventing all slot requests from being successfully + * assigned in a consistent manner and thus hindering the scheduling of the entire job: + * + * <pre> + * the unexpected mapping case: + * - resource request-1: ResourceProfile-1(UNKNOWN) was matched with slot-b: ResourceProfile-b(cpu=2 core, memory=2G) + * - resource request-2: ResourceProfile-2(cpu=2 core, memory=2G) was not matched + * </pre> + * + * Therefore, it is crucial to determine how ResourceProfiles should match before the batch + * allocation of resource requests, aiming to assure the allocation successfully at least. An ideal + * matching relationship would be: + * + * <pre> + * - ResourceProfile-1(UNKNOWN) -> ResourceProfile-a(cpu=1 core, memory=1G) + * - ResourceProfile-2(cpu=2 core, memory=2G) -> ResourceProfile-b(cpu=2 core, memory=2G) + * </pre> + * + * This is the motivation for introducing the current class. + */ +final class ResourceRequestPreMappings { + + private final boolean allMatchable; + // The global variable to keep base mappings result related information, which can assure that + // the allocation for all requests could be run successfully at least. + private final Map<ResourceProfile, Map<ResourceProfile, Integer>> + baseRequiredResourcePreMappings; + // The global variable to keep the remaining available flexible resources besides the + // baseRequiredResourcePreMappings. + private final Map<ResourceProfile, Integer> remainingFlexibleResources; + + private ResourceRequestPreMappings( + boolean allMatchable, + final Map<ResourceProfile, Map<ResourceProfile, Integer>> + baseRequiredResourcePreMappings, + final Map<ResourceProfile, Integer> remainingFlexibleResources) { + this.allMatchable = allMatchable; + + this.baseRequiredResourcePreMappings = + CollectionUtil.newHashMapWithExpectedSize(baseRequiredResourcePreMappings.size()); + this.baseRequiredResourcePreMappings.putAll(baseRequiredResourcePreMappings); + + this.remainingFlexibleResources = + CollectionUtil.newHashMapWithExpectedSize(remainingFlexibleResources.size()); + this.remainingFlexibleResources.putAll(remainingFlexibleResources); + } + + static ResourceRequestPreMappings build( Review Comment: It is strange that there is a build method - I would associate this with a builder. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
