jvm-nmt-tracing

Introduction

This project can give you the internal memory usage of Java Virtual Machine (JVM) via Native Memory Tracking (NMT) feature offered by Java7U40 later version.

Prerequisites

• OpenJDK8 or later version

• Python3

• Launch your Java program by enable NMT feature.

  $ java -XX:NativeMemoryTracking=summary <launch program>

• Then get the <PID> of this java program via jcmd

  $ jcmd

Start tracing

• Launch the tracing program

  $ python3 tracing.py --pid <java program pid> \
                       --target <Target Class of Memory> \
                       --period <Sampling period in sec> \
                       --times <Times of Sampling> \
                       --output-prefix <Output file prefix name>

• Classes of internal memory in JVM

  • Total Committed Memory
  • Java Heap Committed Memory
  • Thread Committed Memory
  • Garbage Collection (GC) Committed Memory
  • Internal Committed Memory

• For example, if I want to track the GC memory usage of the given java progam (pid = 9527) every 5 sec, total 100 times, and recored in ./output.csv file

  $ python3 tracing.py --pid 9527 \
                       --target Total,GC \
                       --period 5 \
                       --times 100 \
                       --output-prefix testing

• There will be new csv files in the current directory

  • testing-Total.csv
  • testing-GC.csv

• Output file is like the following

  < time (sec), Memory Usage (KB) >
  0,2318027
  5,3478519
  10,3587211
  15,3651405
  20,3650761
  25,3658298
  30,3625863
  35,3630655
  40,3716090
  

Licensing

jvm-nmt-tracing is freely redistributable under the MIT License. Use of this source code is governed by a MIT-style license that can be found in the LICENSE file.