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Diffstat (limited to 'framework/src/onos/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/PhiAccrualFailureDetector.java')
| -rw-r--r-- | framework/src/onos/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/PhiAccrualFailureDetector.java | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/framework/src/onos/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/PhiAccrualFailureDetector.java b/framework/src/onos/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/PhiAccrualFailureDetector.java new file mode 100644 index 00000000..cdb138b4 --- /dev/null +++ b/framework/src/onos/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/PhiAccrualFailureDetector.java @@ -0,0 +1,119 @@ +/* + * Copyright 2015 Open Networking Laboratory + * + * Licensed 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.onosproject.store.cluster.impl; + +import static com.google.common.base.Preconditions.checkArgument; +import static com.google.common.base.Preconditions.checkNotNull; + +import java.util.Map; + +import org.apache.commons.math3.stat.descriptive.DescriptiveStatistics; +import org.onosproject.cluster.NodeId; + +import com.google.common.collect.Maps; + +/** + * Phi Accrual failure detector. + * <p> + * Based on a paper titled: "The φ Accrual Failure Detector" by Hayashibara, et al. + */ +public class PhiAccrualFailureDetector { + private final Map<NodeId, History> states = Maps.newConcurrentMap(); + + // TODO: make these configurable. + private static final int WINDOW_SIZE = 250; + private static final int MIN_SAMPLES = 25; + private static final double PHI_FACTOR = 1.0 / Math.log(10.0); + + // If a node does not have any heartbeats, this is the phi + // value to report. Indicates the node is inactive (from the + // detectors perspective. + private static final double BOOTSTRAP_PHI_VALUE = 100.0; + + /** + * Report a new heart beat for the specified node id. + * @param nodeId node id + */ + public void report(NodeId nodeId) { + report(nodeId, System.currentTimeMillis()); + } + + /** + * Report a new heart beat for the specified node id. + * @param nodeId node id + * @param arrivalTime arrival time + */ + public void report(NodeId nodeId, long arrivalTime) { + checkNotNull(nodeId, "NodeId must not be null"); + checkArgument(arrivalTime >= 0, "arrivalTime must not be negative"); + History nodeState = + states.computeIfAbsent(nodeId, key -> new History()); + synchronized (nodeState) { + long latestHeartbeat = nodeState.latestHeartbeatTime(); + if (latestHeartbeat != -1) { + nodeState.samples().addValue(arrivalTime - latestHeartbeat); + } + nodeState.setLatestHeartbeatTime(arrivalTime); + } + } + + /** + * Compute phi for the specified node id. + * @param nodeId node id + * @return phi value + */ + public double phi(NodeId nodeId) { + checkNotNull(nodeId, "NodeId must not be null"); + if (!states.containsKey(nodeId)) { + return BOOTSTRAP_PHI_VALUE; + } + History nodeState = states.get(nodeId); + synchronized (nodeState) { + long latestHeartbeat = nodeState.latestHeartbeatTime(); + DescriptiveStatistics samples = nodeState.samples(); + if (latestHeartbeat == -1 || samples.getN() < MIN_SAMPLES) { + return 0.0; + } + return computePhi(samples, latestHeartbeat, System.currentTimeMillis()); + } + } + + private double computePhi(DescriptiveStatistics samples, long tLast, long tNow) { + long size = samples.getN(); + long t = tNow - tLast; + return (size > 0) + ? PHI_FACTOR * t / samples.getMean() + : BOOTSTRAP_PHI_VALUE; + } + + private static class History { + DescriptiveStatistics samples = + new DescriptiveStatistics(WINDOW_SIZE); + long lastHeartbeatTime = -1; + + public DescriptiveStatistics samples() { + return samples; + } + + public long latestHeartbeatTime() { + return lastHeartbeatTime; + } + + public void setLatestHeartbeatTime(long value) { + lastHeartbeatTime = value; + } + } +}
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