HDFS-14403. Cost-based extension to the RPC Fair Call Queue. Contributed by Christopher Gregorian.

Author: csgregorian

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/CommonConfigurationKeys.java

@@ -106,6 +106,7 @@ public class CommonConfigurationKeys extends CommonConfigurationKeysPublic {
   public static final String IPC_CALLQUEUE_IMPL_KEY = "callqueue.impl";
   public static final String IPC_SCHEDULER_IMPL_KEY = "scheduler.impl";
   public static final String IPC_IDENTITY_PROVIDER_KEY = "identity-provider.impl";
+  public static final String IPC_COST_PROVIDER_KEY = "cost-provider.impl";
   public static final String IPC_BACKOFF_ENABLE = "backoff.enable";
   public static final boolean IPC_BACKOFF_ENABLE_DEFAULT = false;
 

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/CallQueueManager.java

@@ -198,7 +198,6 @@ void addResponseTime(String name, Schedulable e, ProcessingDetails details) {
   }
 
   // This should be only called once per call and cached in the call object
-  // each getPriorityLevel call will increment the counter for the caller
   int getPriorityLevel(Schedulable e) {
     return scheduler.getPriorityLevel(e);
   }

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/CostProvider.java

@@ -0,0 +1,46 @@
+/**
+ * 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.ipc;
+
+import org.apache.hadoop.conf.Configuration;
+
+/**
+ * Used by {@link DecayRpcScheduler} to get the cost of users' operations. This
+ * is configurable using
+ * {@link org.apache.hadoop.fs.CommonConfigurationKeys#IPC_COST_PROVIDER_KEY}.
+ */
+public interface CostProvider {
+
+  /**
+   * Initialize this provider using the given configuration, examining only
+   * ones which fall within the provided namespace.
+   *
+   * @param namespace The namespace to use when looking up configurations.
+   * @param conf The configuration
+   */
+  void init(String namespace, Configuration conf);
+
+  /**
+   * Get cost from {@link ProcessingDetails} which will be used in scheduler.
+   *
+   * @param details Process details
+   * @return The cost of the call
+   */
+  long getCost(ProcessingDetails details);
+}