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Posted to issues@flink.apache.org by GitBox <gi...@apache.org> on 2022/06/27 09:49:03 UTC
[GitHub] [flink] zhuzhurk commented on a diff in pull request #20072: [FLINK-28136][runtime] Implement ExecutionTimeBasedSlowTaskDetector
zhuzhurk commented on code in PR #20072:
URL: https://github.com/apache/flink/pull/20072#discussion_r907158982
##########
flink-runtime/src/main/java/org/apache/flink/runtime/executiongraph/ExecutionVertex.java:
##########
@@ -242,6 +242,10 @@ public Execution getCurrentExecutionAttempt() {
return currentExecution;
}
+ public List<Execution> getCurrentExecutionAttempts() {
+ return Collections.singletonList(currentExecution);
+ }
Review Comment:
```suggestion
public Collection<Execution> getCurrentExecutions() {
return Collections.singleton(currentExecution);
}
```
So that it can be aligned with #20082. The benefit is that we can create an unmodifiable collection in `SpeculativeExecutionVertex` with little cost.
##########
flink-runtime/src/main/java/org/apache/flink/runtime/scheduler/slowtaskdetector/ExecutionTimeBasedSlowTaskDetector.java:
##########
@@ -0,0 +1,211 @@
+/*
+ * 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.scheduler.slowtaskdetector;
+
+import org.apache.flink.annotation.VisibleForTesting;
+import org.apache.flink.configuration.Configuration;
+import org.apache.flink.configuration.SlowTaskDetectorOptions;
+import org.apache.flink.runtime.concurrent.ComponentMainThreadExecutor;
+import org.apache.flink.runtime.execution.ExecutionState;
+import org.apache.flink.runtime.executiongraph.Execution;
+import org.apache.flink.runtime.executiongraph.ExecutionAttemptID;
+import org.apache.flink.runtime.executiongraph.ExecutionGraph;
+import org.apache.flink.runtime.executiongraph.ExecutionJobVertex;
+import org.apache.flink.runtime.executiongraph.ExecutionVertex;
+import org.apache.flink.runtime.scheduler.strategy.ExecutionVertexID;
+import org.apache.flink.util.IterableUtils;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+import static org.apache.flink.util.Preconditions.checkState;
+
+/** The slow task detector which detects slow tasks based on their execution time. */
+public class ExecutionTimeBasedSlowTaskDetector implements SlowTaskDetector {
+
+ private final long checkIntervalMillis;
+
+ private final long baselineLowerBoundMillis;
+
+ private final double baselineRatio;
+
+ private final double baselineMultiplier;
+
+ private ScheduledFuture<?> scheduledDetectionFuture;
+
+ public ExecutionTimeBasedSlowTaskDetector(Configuration configuration) {
+ this.checkIntervalMillis =
+ configuration.get(SlowTaskDetectorOptions.CHECK_INTERVAL).toMillis();
+ this.baselineLowerBoundMillis =
+ configuration
+ .get(SlowTaskDetectorOptions.EXECUTION_TIME_BASELINE_LOWER_BOUND)
+ .toMillis();
+ this.baselineRatio =
+ configuration.getDouble(SlowTaskDetectorOptions.EXECUTION_TIME_BASELINE_RATIO);
+ this.baselineMultiplier =
+ configuration.getDouble(SlowTaskDetectorOptions.EXECUTION_TIME_BASELINE_MULTIPLIER);
+ }
+
+ @Override
+ public void start(
+ final ExecutionGraph executionGraph,
+ final SlowTaskDetectorListener listener,
+ final ComponentMainThreadExecutor mainThreadExecutor) {
+ scheduleTask(executionGraph, listener, mainThreadExecutor);
+ }
+
+ /** Schedule periodical slow task detection. */
+ private void scheduleTask(
+ final ExecutionGraph executionGraph,
+ final SlowTaskDetectorListener listener,
+ final ComponentMainThreadExecutor mainThreadExecutor) {
+ this.scheduledDetectionFuture =
+ mainThreadExecutor.schedule(
+ () -> {
+ listener.notifySlowTasks(findSlowTasks(executionGraph));
+ scheduleTask(executionGraph, listener, mainThreadExecutor);
+ },
+ checkIntervalMillis,
+ TimeUnit.MILLISECONDS);
+ }
+
+ /**
+ * Given that the parallelism is N and the ratio is R, define T as the median of the first N*R
+ * finished tasks' execution time. The baseline will be T*M, where M is the multiplier. A task
+ * will be identified as slow if its execution time is longer than the baseline.
+ */
+ @VisibleForTesting
+ Map<ExecutionVertexID, Collection<ExecutionAttemptID>> findSlowTasks(
+ final ExecutionGraph executionGraph) {
+ final long currentTimeMillis = System.currentTimeMillis();
+
+ final Map<ExecutionVertexID, Collection<ExecutionAttemptID>> slowTasks = new HashMap<>();
+
+ final List<ExecutionJobVertex> jobVerticesToCheck = getJobVerticesToCheck(executionGraph);
+
+ for (ExecutionJobVertex ejv : jobVerticesToCheck) {
+ final long baseline = getBaseline(ejv, currentTimeMillis);
+
+ for (ExecutionVertex ev : ejv.getTaskVertices()) {
+ if (ev.getExecutionState().isTerminal()) {
+ continue;
+ }
+
+ final List<ExecutionAttemptID> slowExecutions =
+ findExecutionsExceedingBaseline(
+ ev.getCurrentExecutionAttempts(), baseline, currentTimeMillis);
+
+ if (!slowExecutions.isEmpty()) {
+ slowTasks.put(ev.getID(), slowExecutions);
+ }
+ }
+ }
+
+ return slowTasks;
+ }
+
+ private List<ExecutionJobVertex> getJobVerticesToCheck(final ExecutionGraph executionGraph) {
+ return IterableUtils.toStream(executionGraph.getVerticesTopologically())
+ .filter(ejv -> ejv.isInitialized())
+ .filter(ejv -> ejv.getAggregateState() != ExecutionState.FINISHED)
+ .filter(ejv -> getFinishedRatio(ejv) >= baselineRatio)
+ .collect(Collectors.toList());
+ }
+
+ private double getFinishedRatio(final ExecutionJobVertex executionJobVertex) {
+ checkState(executionJobVertex.getTaskVertices().length > 0);
+ long finishedCount =
+ Arrays.stream(executionJobVertex.getTaskVertices())
+ .filter(ev -> ev.getExecutionState() == ExecutionState.FINISHED)
+ .count();
+ return Double.valueOf(finishedCount) / executionJobVertex.getTaskVertices().length;
+ }
+
+ private long getBaseline(
+ final ExecutionJobVertex executionJobVertex, final long currentTimeMillis) {
+ final long executionTimeMedian =
+ calculateFinishedTaskExecutionTimeMedian(executionJobVertex, currentTimeMillis);
+ return (long) Math.max(baselineLowerBoundMillis, executionTimeMedian * baselineMultiplier);
+ }
+
+ private long calculateFinishedTaskExecutionTimeMedian(
+ final ExecutionJobVertex executionJobVertex, final long currentTime) {
+
+ final int baselineExecutionCount =
+ Double.valueOf(Math.round(executionJobVertex.getParallelism() * baselineRatio))
+ .intValue();
+
+ if (baselineExecutionCount == 0) {
+ return 0;
+ }
+
+ final List<Execution> finishedExecutions =
+ Arrays.stream(executionJobVertex.getTaskVertices())
+ .flatMap(ev -> ev.getCurrentExecutionAttempts().stream())
+ .filter(e -> e.getState() == ExecutionState.FINISHED)
+ .collect(Collectors.toList());
+
+ checkState(finishedExecutions.size() >= baselineExecutionCount);
+
+ final List<Long> firstFinishedExecutions =
+ finishedExecutions.stream()
+ .map(e -> getExecutionTime(e, currentTime))
+ .sorted()
+ .limit(baselineExecutionCount)
+ .collect(Collectors.toList());
+
+ return firstFinishedExecutions.get(baselineExecutionCount / 2);
+ }
+
+ private List<ExecutionAttemptID> findExecutionsExceedingBaseline(
+ Collection<Execution> executions, long baseline, long currentTimeMillis) {
+ return executions.stream()
+ .filter(e -> !e.getState().isTerminal() && e.getState() != ExecutionState.CANCELING)
+ .filter(e -> getExecutionTime(e, currentTimeMillis) >= baseline)
+ .map(Execution::getAttemptId)
+ .collect(Collectors.toList());
+ }
+
+ private long getExecutionTime(final Execution execution, final long currentTime) {
Review Comment:
`System.currentTimeMillis()` is a heavy operation and we should avoid it if possible.
##########
flink-runtime/src/main/java/org/apache/flink/runtime/scheduler/slowtaskdetector/ExecutionTimeBasedSlowTaskDetector.java:
##########
@@ -0,0 +1,211 @@
+/*
+ * 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.scheduler.slowtaskdetector;
+
+import org.apache.flink.annotation.VisibleForTesting;
+import org.apache.flink.configuration.Configuration;
+import org.apache.flink.configuration.SlowTaskDetectorOptions;
+import org.apache.flink.runtime.concurrent.ComponentMainThreadExecutor;
+import org.apache.flink.runtime.execution.ExecutionState;
+import org.apache.flink.runtime.executiongraph.Execution;
+import org.apache.flink.runtime.executiongraph.ExecutionAttemptID;
+import org.apache.flink.runtime.executiongraph.ExecutionGraph;
+import org.apache.flink.runtime.executiongraph.ExecutionJobVertex;
+import org.apache.flink.runtime.executiongraph.ExecutionVertex;
+import org.apache.flink.runtime.scheduler.strategy.ExecutionVertexID;
+import org.apache.flink.util.IterableUtils;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+import static org.apache.flink.util.Preconditions.checkState;
+
+/** The slow task detector which detects slow tasks based on their execution time. */
+public class ExecutionTimeBasedSlowTaskDetector implements SlowTaskDetector {
+
+ private final long checkIntervalMillis;
+
+ private final long baselineLowerBoundMillis;
+
+ private final double baselineRatio;
+
+ private final double baselineMultiplier;
+
+ private ScheduledFuture<?> scheduledDetectionFuture;
+
+ public ExecutionTimeBasedSlowTaskDetector(Configuration configuration) {
+ this.checkIntervalMillis =
+ configuration.get(SlowTaskDetectorOptions.CHECK_INTERVAL).toMillis();
+ this.baselineLowerBoundMillis =
+ configuration
+ .get(SlowTaskDetectorOptions.EXECUTION_TIME_BASELINE_LOWER_BOUND)
+ .toMillis();
+ this.baselineRatio =
+ configuration.getDouble(SlowTaskDetectorOptions.EXECUTION_TIME_BASELINE_RATIO);
+ this.baselineMultiplier =
+ configuration.getDouble(SlowTaskDetectorOptions.EXECUTION_TIME_BASELINE_MULTIPLIER);
+ }
+
+ @Override
+ public void start(
+ final ExecutionGraph executionGraph,
+ final SlowTaskDetectorListener listener,
+ final ComponentMainThreadExecutor mainThreadExecutor) {
+ scheduleTask(executionGraph, listener, mainThreadExecutor);
+ }
+
+ /** Schedule periodical slow task detection. */
+ private void scheduleTask(
+ final ExecutionGraph executionGraph,
+ final SlowTaskDetectorListener listener,
+ final ComponentMainThreadExecutor mainThreadExecutor) {
+ this.scheduledDetectionFuture =
+ mainThreadExecutor.schedule(
+ () -> {
+ listener.notifySlowTasks(findSlowTasks(executionGraph));
+ scheduleTask(executionGraph, listener, mainThreadExecutor);
+ },
+ checkIntervalMillis,
+ TimeUnit.MILLISECONDS);
+ }
+
+ /**
+ * Given that the parallelism is N and the ratio is R, define T as the median of the first N*R
+ * finished tasks' execution time. The baseline will be T*M, where M is the multiplier. A task
+ * will be identified as slow if its execution time is longer than the baseline.
+ */
+ @VisibleForTesting
+ Map<ExecutionVertexID, Collection<ExecutionAttemptID>> findSlowTasks(
+ final ExecutionGraph executionGraph) {
+ final long currentTimeMillis = System.currentTimeMillis();
+
+ final Map<ExecutionVertexID, Collection<ExecutionAttemptID>> slowTasks = new HashMap<>();
+
+ final List<ExecutionJobVertex> jobVerticesToCheck = getJobVerticesToCheck(executionGraph);
+
+ for (ExecutionJobVertex ejv : jobVerticesToCheck) {
+ final long baseline = getBaseline(ejv, currentTimeMillis);
+
+ for (ExecutionVertex ev : ejv.getTaskVertices()) {
+ if (ev.getExecutionState().isTerminal()) {
+ continue;
+ }
+
+ final List<ExecutionAttemptID> slowExecutions =
+ findExecutionsExceedingBaseline(
+ ev.getCurrentExecutionAttempts(), baseline, currentTimeMillis);
+
+ if (!slowExecutions.isEmpty()) {
+ slowTasks.put(ev.getID(), slowExecutions);
+ }
+ }
+ }
+
+ return slowTasks;
+ }
+
+ private List<ExecutionJobVertex> getJobVerticesToCheck(final ExecutionGraph executionGraph) {
+ return IterableUtils.toStream(executionGraph.getVerticesTopologically())
+ .filter(ejv -> ejv.isInitialized())
+ .filter(ejv -> ejv.getAggregateState() != ExecutionState.FINISHED)
+ .filter(ejv -> getFinishedRatio(ejv) >= baselineRatio)
+ .collect(Collectors.toList());
+ }
+
+ private double getFinishedRatio(final ExecutionJobVertex executionJobVertex) {
+ checkState(executionJobVertex.getTaskVertices().length > 0);
+ long finishedCount =
+ Arrays.stream(executionJobVertex.getTaskVertices())
+ .filter(ev -> ev.getExecutionState() == ExecutionState.FINISHED)
+ .count();
+ return Double.valueOf(finishedCount) / executionJobVertex.getTaskVertices().length;
+ }
+
+ private long getBaseline(
+ final ExecutionJobVertex executionJobVertex, final long currentTimeMillis) {
+ final long executionTimeMedian =
+ calculateFinishedTaskExecutionTimeMedian(executionJobVertex, currentTimeMillis);
+ return (long) Math.max(baselineLowerBoundMillis, executionTimeMedian * baselineMultiplier);
+ }
+
+ private long calculateFinishedTaskExecutionTimeMedian(
+ final ExecutionJobVertex executionJobVertex, final long currentTime) {
+
+ final int baselineExecutionCount =
+ Double.valueOf(Math.round(executionJobVertex.getParallelism() * baselineRatio))
+ .intValue();
Review Comment:
```suggestion
(int) Math.round(executionJobVertex.getParallelism() * baselineRatio);
```
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