[GitHub] [samza] mynameborat commented on a diff in pull request #1636: SAMZA-2762: new cpu usage metric which counts child processes usage

[GitBox <gi...@apache.org>]

mynameborat commented on code in PR #1636:
URL: https://github.com/apache/samza/pull/1636#discussion_r1013440757


##########
samza-core/src/main/java/org/apache/samza/container/host/DefaultSystemStatisticsGetter.java:
##########
@@ -0,0 +1,53 @@
+/*
+ * 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.samza.container.host;
+
+import com.google.common.annotations.VisibleForTesting;
+
+
+/**
+ * An default implementation of {@link SystemStatisticsGetter} that relies on {@link PosixCommandBasedStatisticsGetter}
+ * and {@link OshiBasedStatisticsGetter} implementations
+ */
+public class DefaultSystemStatisticsGetter implements SystemStatisticsGetter {
+

Review Comment:
   nit: remove extra line



##########
samza-core/src/main/java/org/apache/samza/container/host/ProcessCPUStatistics.java:
##########
@@ -0,0 +1,63 @@
+/*
+ * 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.samza.container.host;
+
+import java.util.Objects;
+
+
+/**
+ * A {@link ProcessCPUStatistics} object represents recent CPU usage percentage about the container process(including its child processes)
+ */
+public class ProcessCPUStatistics {

Review Comment:
   why do we need to wrap this into a container object? 



##########
samza-core/src/main/java/org/apache/samza/container/host/OshiBasedStatisticsGetter.java:
##########
@@ -0,0 +1,90 @@
+/*
+ * 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.samza.container.host;
+
+import com.google.common.annotations.VisibleForTesting;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import org.apache.commons.lang3.NotImplementedException;
+import oshi.SystemInfo;
+import oshi.software.os.OSProcess;
+import oshi.software.os.OperatingSystem;
+
+
+/**
+ * An implementation of {@link SystemStatisticsGetter} that relies on using oshi framework(https://www.oshi.ooo/)
+ */
+public class OshiBasedStatisticsGetter implements SystemStatisticsGetter {
+  // the snapshots of current JVM process and its child processes
+  private final Map<Integer, OSProcess> previousProcessSnapshots = new HashMap<>();
+
+  private final OperatingSystem os;
+  private final int cpuCount;
+
+  public OshiBasedStatisticsGetter() {
+    this(new SystemInfo());
+  }
+
+  @VisibleForTesting
+  OshiBasedStatisticsGetter(SystemInfo si) {
+    this(si.getOperatingSystem(), si.getHardware().getProcessor().getPhysicalProcessorCount());
+  }
+
+  @VisibleForTesting
+  OshiBasedStatisticsGetter(OperatingSystem os, int cpuCount) {
+    this.os = os;
+    this.cpuCount = cpuCount;
+  }
+
+  @Override
+  public SystemMemoryStatistics getSystemMemoryStatistics() {
+    throw new NotImplementedException("Not implemented");
+  }
+
+  @Override
+  public ProcessCPUStatistics getProcessCPUStatistics() {
+    final List<OSProcess> currentProcessAndChildProcesses = getCurrentProcessAndChildProcesses();
+    final double totalCPUUsage = getTotalCPUUsage(currentProcessAndChildProcesses);
+    refreshProcessSnapshots(currentProcessAndChildProcesses);
+    return new ProcessCPUStatistics(100d * totalCPUUsage / cpuCount);
+  }
+
+  private List<OSProcess> getCurrentProcessAndChildProcesses() {
+    final List<OSProcess> processes = new ArrayList<>();
+    // get current process
+    processes.add(os.getProcess(os.getProcessId()));
+    // get all child processes of current process
+    processes.addAll(os.getChildProcesses(os.getProcessId(), OperatingSystem.ProcessFiltering.ALL_PROCESSES,
+        OperatingSystem.ProcessSorting.NO_SORTING, 0));
+    return processes;
+  }
+
+  private double getTotalCPUUsage(List<OSProcess> processes) {
+    return processes.stream()
+        .mapToDouble(p -> p.getProcessCpuLoadBetweenTicks(previousProcessSnapshots.get(p.getProcessID())))

Review Comment:
   What is the behavior if `previousProcessSnapshots.get(...)` returns `null`? 
   Will `getProcessCpuLoadBetweenTicks(null)` throw errors?



##########
samza-core/src/main/java/org/apache/samza/container/host/PosixCommandBasedStatisticsGetter.java:
##########
@@ -85,4 +86,10 @@ public SystemMemoryStatistics getSystemMemoryStatistics() {
       return null;
     }
   }
+
+  @Override
+  public ProcessCPUStatistics getProcessCPUStatistics() {
+    throw new NotImplementedException(
+        "No appropriate Posix command available for getting recent CPU usage information. For example, the CPU information exposed by ps command 'ps -o %cpu= -p <PID>' represents the percentage of time spent running during the entire lifetime of a process not for the recent CPU usage");
+  }

Review Comment:
   Why not `top`?



##########
samza-core/src/main/scala/org/apache/samza/container/SamzaContainerMetrics.scala:
##########
@@ -49,6 +49,7 @@ class SamzaContainerMetrics(
   val executorWorkFactor = newGauge("executor-work-factor", 1.0)
   val physicalMemoryMb = newGauge("physical-memory-mb", 0.0F)
   val physicalMemoryUtilization = newGauge("physical-memory-utilization", 0.0F)
+  val totalProcessCpuUsage = newGauge("total-process-cpu-usage", 0.0)

Review Comment:
   We are not rolling into the existing metrics is it? Why so? 
   If we want to keep it separate, can we add documentation about the new metric to the website docs?



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