JoularJX 🔬

JoularJX is a Java-based agent for software power monitoring at the source code level.

Detailed documentation (including user and reference guides) are available at: https://joular.github.io/joularjx/.

🚀 Features

• Monitor power consumption of each method at runtime
• Uses a Java agent, no source code instrumentation needed
• Uses Intel RAPL (powercap interface) for getting accurate power reading on GNU/Linux, our research-based regression models on Raspberry Pi devices, and a custom program monitor (using a RAPL driver) for accurate power readings on Windows
• Monitor energy of Java applications running in virtual machines
• Provides real-time power consumption of every method in the monitored program
• Provides total energy for every method on program exit

📦 Compilation and Installation

To build JoularJX, you need Java 11+ and Maven, then just build:

mvn clean install

Alternatively, you can use the Maven wrapper shipped with the project with the command:

Linux: ./mvnw clean install
Windows: ./mvnw.cmd clean install

JoularJX gets CPU power reading from various sources, depending on the platform or operating system. In particuliar, it can get the data from two main approaches:

• Get the power data from Joular Core, either through its standard output or through a shared memory buffer ring (IPC). Joular Core works on all platforms and operating systems.
• Get the data through its internal calculation from RAPL (Linux, Windows), powermetrics (macOS) or our own regression models (Raspberry Pi).
• In addition, in virtual machines, JoularJX reads the power consumption of the virtual machine (measured in the host) from a file shared between the host and the guest.

If using JoularJX internal calculation, you need:

• On Windows, to read the data from the RAPL driver, we use a custom program monitor called Power Monitor for Windows. It used to be part of JoularJX, but now it is in its own repository. Download the binary (or compile the source code), and specify its path in config.properties. Runs on Intel or AMD CPUs (since Ryzen). You can substitute that software with Joular Core.
• On PC/server GNU/Linux, JoularJX uses Intel RAPL interface through powercap, and therefore requires running on an Intel CPU or an AMD CPU (since Ryzen).
• On macOS, JoularJX uses powermetrics, a tool bundled with macOS which requires running with sudo access. It is recommended to authorize the current users to run /usr/bin/powermetrics without requiring a password by making the proper modification to the sudoers file.
• On Raspberry Pi devices on GNU/Linux, JoularJX uses our own research-based regression models to estimate CPU power consumption with support for the following device models (we support all revisions of each model lineup. However, the model is generated and trained on a specific revision, listed between brackets, and the accuracy is best on this particular revision):
  • Model Zero W (rev 1.1), for 32-bit OS
  • Model 1 B (rev 2), for 32-bit OS
  • Model 1 B+ (rev 1.2), for 32-bit OS
  • Model 2 B (rev 1.1), for 32-bit OS
  • Model 3 B (rev 1.2), for 32-bit OS
  • Model 3 B+ (rev 1.3), for 32-bit OS
  • Model 4 B (rev 1.1, and rev 1.2), for both 32 bits and 64-bit OS
  • Model 400 (rev 1.0), for 64-bit OS
  • Model 5 B (rev 1.0), for 64-bit OS We also support Asus Tinker Board (S).

💡 Usage

JoularJX is a Java agent where you can simply hook it to the Java Virtual Machine when starting your Java program's main class:

java -javaagent:joularjx-$version.jar YourProgramMainClass

If your program is a JAR file, then just run it as usual while adding JoularJX:

java -javaagent:joularjx-$version.jar -jar yourProgram.jar

JoularJX will generate multiple CSV files according to the configuration settings (in config.properties), and will create these files in a joularjx-resultsfolder.

The generated files are available under the following folder structure:

• joularjx-results
  • appName-PID-start_timestamp
    • all (power/energy data for all methods, including the JDK ones)
      • runtime (power consumption every second)
        • calltree (consumption for each call tree branch)
        • methods (consumption for each methods)
      • total (total energy consumption, generated at the program's end)
        • calltree
        • methods
      • evolution (power consumption evolution of every method, throughout the execution of the application)
    • app (power/energy data for methods of the monitored application, according to the filter-method-names setting)
      • runtime
        • calltree
        • methods
      • total
        • calltree
        • methods
      • evolution

JoularJX can be configured by modifying the config.properties files:

• filter-method-names: list of strings which will be used to filter the monitored methods (see Generated files below for explanations).
• save-runtime-data: write runtime methods power consumption in a CSV file.
• overwrite-runtime-data: overwrite runtime power data files, or if set to false, it will write new files for each monitoring cycle.
• logger-level: set the level of information (by logger) given by JoularJX in the terminal (allowed values: OFF, INFO, WARNING, SEVERE).
• powermonitor-path: Full path to the Power Monitor for Windows program (only for Windows).
• track-consumption-evolution: generate CSV files for each method containing details of the method's consumption over the time. Each consumption value is mapped to an Unix timestamp.
• hide-agent-consumption: if set to true, the energy consumption of the agent threads will not be reported.
• enable-call-trees-consumption: compute methods call trees energy consumption. A CSV file will be generated at the end of the agent's execution, associating to each call tree it's total energy consumption.
• save-call-trees-runtime-data: write runtime call trees power consumption in a CSV file. For each monitoring cycle (1 second), a new CSV file will be generated, containing the runtime power consumption of the call trees. The generated files will include timestamps in their names.
• overwrite-call-trees-runtime-data: overwrite runtime call trees power data file, or if set to false, it will write new file for each monitoring cycle.
• application-server: properly handles application servers and frameworks (Sprig Boot, Tomcat, etc.). Set true when running on application servers. If false, the monitoring loop will check if the JVM is destroyed, hence closing JoularJX when the application ends (in regular Java application). If true, JoularJX will continue to monitor correctly as the JVM isn't destroyed in a application server.
• vm-power-path: the path for the power consumption of the virtual machine. Inside a virtual machine, indicate the file containing power consumption of the VM (which is usually a file in the host that is shared with the guest).
• vm-power-format: power format of the shared VM power file. We currently support two formats: watts (a file containing one float value which is the power consumption of the VM), and powerjoular (a csv file generated by PowerJoular in the host, containing 3 columns: timestamp, CPU utilization of the VM and CPU power of the VM).
• joular-core: if set to true, use Joular Core instead of JoularJX internal CPU power calculations.
• joular-core-ring-buffer: if Joular Core is set to true, and this property is also set to true, then get power data from Joular Core through a shareed memory ring buffer.
• joular-core-path: the full path of Joular Core binary.
• joular-core-parameters: the parameters to run Joular Core with. It must be -c cpu -i.
• joular-core-ringbuffer-path: the path to Joular Core ring buffer.

You can install the jar package (and the PowerMonitor.exe on Windows) wherever you want, and call it in the javaagent with the full path. However, config.properties must either be copied to the same folder as where you run the Java command or its location must be set with the -Djoularjx.config=/path/to/config.properties property when running your program.

In virtual machines, JoularJX requires two steps:

• Installing a power monitoring tool in the host machine, which will monitor the virtual machine power consumption every second and writing it to a file (to be shared with the guest VM). For example, you can use our tools: Joular Core or PowerJoular.
• Use JoularJ in the guest VM while specifying the path of the power file shared with the host and its format.

Generated files

For real-time power data or the total energy at the program exit, JoularJX generated two CSV files:

• A file which contains power or energy data for all methods, which include the JDK's ones.
• A filtered file which only includes the power or energy data of those filtered methods (can be configured in config.properties). This data is not just a subset of the first data file, but rather a recalculation done by JoularJX to provide accurate data: methods that start with the filtered keyword, will be allocated the power or energy consumed by the JDK methods that it calls.

For example, if Package1.MethodA calls java.io.PrintStream.println to print some text to a terminal, then we calculate:

• In the first file, the power or energy consumed by println separately from MethodA. The latter power consumption won't include those consumed by println.
• In the second file, if we filter methods from Package1, then the power consumption of println will be added to MethodA power consumption, and the file will only provide power or energy of Package1 methods.

We manage to do this by analyzing the stacktrace of all running threads on runtime.

JoularJX Reader

JoularJX Reader is a GUI to process, analyze and visualize JoularJX generated energy files. It is available at its own repository here.

📑 Cite this work

To cite our work in a research paper, please cite our paper in the 18th International Conference on Intelligent Environments (IE2022).

• PowerJoular and JoularJX: Multi-Platform Software Power Monitoring Tools. Adel Noureddine. In the 18th International Conference on Intelligent Environments (IE2022). Biarritz, France, 2022.

@inproceedings{noureddine-ie-2022,
  title = {PowerJoular and JoularJX: Multi-Platform Software Power Monitoring Tools},
  author = {Noureddine, Adel},
  booktitle = {18th International Conference on Intelligent Environments (IE2022)},
  address = {Biarritz, France},
  year = {2022},
  month = {Jun},
  keywords = {Power Monitoring; Measurement; Power Consumption; Energy Analysis}
}

📰 License

JoularJX is licensed under the GNU GPL 3 license only (GPL-3.0-only).

Copyright (c) 2021-2026, Adel Noureddine, Université de Pau et des Pays de l'Adour. All rights reserved. This program and the accompanying materials are made available under the terms of the GNU General Public License v3.0 only (GPL-3.0-only) which accompanies this distribution, and is available at: https://www.gnu.org/licenses/gpl-3.0.en.html

Author : Adel Noureddine