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

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

alnzng commented on code in PR #1636:
URL: https://github.com/apache/samza/pull/1636#discussion_r1014522272


##########
samza-core/src/main/java/org/apache/samza/container/host/OshiBasedStatisticsGetter.java:
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@@ -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);

Review Comment:
   The existing CPU reporting actually takes into account the core-count on the host, right? Because it leverages on Java function `OperatingSystemMXBean. getProcessCpuLoad ()` whose value is a double in the [0.0,1.0] interval. If not, the value could be larger than 1.0.
   
   https://docs.oracle.com/javase/8/docs/jre/api/management/extension/com/sun/management/OperatingSystemMXBean.html#getProcessCpuTime--
   
   >Returns the "recent cpu usage" for the Java Virtual Machine process. This value is a double in the [0.0,1.0] interval. A value of 0.0 means that none of the CPUs were running threads from the JVM process during the recent period of time observed, while a value of 1.0 means that all CPUs were actively running threads from the JVM 100% of the time during the recent period being observed. Threads from the JVM include the application threads as well as the JVM internal threads. All values betweens 0.0 and 1.0 are possible depending of the activities going on in the JVM process and the whole system. If the Java Virtual Machine recent CPU usage is not available, the method returns a negative value.
   



##########
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;

Review Comment:
    I found some classes used this `NotImplementedException ` class so I used it here. I'm good with `UnsupportedOperationException`, I can change it.



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