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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.hdfs.client.impl.metrics;
import com.facebook.presto.hadoop.$internal.com.google.common.annotations.VisibleForTesting;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.metrics2.MetricsSystem;
import org.apache.hadoop.metrics2.annotation.Metric;
import org.apache.hadoop.metrics2.annotation.Metrics;
import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
import org.apache.hadoop.metrics2.lib.MutableRollingAverages;
/**
* This class maintains a metric of rolling average latency for short circuit
* reads.
*/
@InterfaceAudience.Private
@Metrics(name="HdfsShortCircuitReads",
about="Block Reader Local's Short Circuit Read latency",
context="dfs")
public class BlockReaderLocalMetrics {
@Metric(value = "short circuit read operation rate", valueName = "LatencyMs")
private MutableRollingAverages shortCircuitReadRollingAverages;
private static final String SHORT_CIRCUIT_READ_METRIC_REGISTERED_NAME =
"HdfsShortCircuitReads";
private static final String SHORT_CIRCUIT_LOCAL_READS_METRIC_VALUE_NAME =
"ShortCircuitLocalReads";
public static BlockReaderLocalMetrics create() {
MetricsSystem ms = DefaultMetricsSystem.instance();
BlockReaderLocalMetrics metrics = new BlockReaderLocalMetrics();
ms.register(
SHORT_CIRCUIT_READ_METRIC_REGISTERED_NAME, null, metrics);
return metrics;
}
/**
* Adds short circuit read elapsed time.
*/
public void addShortCircuitReadLatency(final long latency) {
shortCircuitReadRollingAverages.add(
SHORT_CIRCUIT_LOCAL_READS_METRIC_VALUE_NAME, latency);
}
/**
* Collects states maintained in {@link ThreadLocal}, if any.
*/
public void collectThreadLocalStates() {
shortCircuitReadRollingAverages.collectThreadLocalStates();
}
/**
* Get the MutableRollingAverage metric for testing only.
* @return
*/
@VisibleForTesting
public MutableRollingAverages getShortCircuitReadRollingAverages() {
return shortCircuitReadRollingAverages;
}
}
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