perun is a Python package that calculates the energy consumption of Python scripts by sampling usage statistics from hardware interfaces. It can handle MPI applications, gather data from hundreds of nodes, and accumulate it efficiently.


Cite this software

What perun can do for you OpenSSF Best Practices DOI PyPI PyPI - Downloads Code style: black License Documentation Status

perun is a Python package that calculates the energy consumption of Python scripts by sampling usage statistics from Intel RAPL, Nvidia-NVML, and psutil. It can handle MPI applications, gather data from hundreds of nodes, and accumulate it efficiently. perun can be used as a command-line tool or as a function decorator in Python scripts.

Check out the docs or a working example!

Key Features

  • Measures energy consumption of Python scripts using Intel RAPL, Nvidia-NVML, and psutil
  • Handles MPI applications efficiently
  • Gathers data from hundreds of nodes and accumulates it efficiently
  • Monitor individual functions using decorators
  • Tracks energy usage of the application over multiple executions
  • Easy to benchmark applications and functions


From PyPI:

pip install perun

From Github:

pip install git+

Quick Start

Command Line

To use perun as a command-line tool, run the monitor subcommand followed by the path to your Python script and its arguments:

$ perun monitor path/to/your/ [args]

perun will output two files, and HDF5 style containing all the raw data that was gathered, and a text file with a summary of the results.


App name: finetune_qa_accelerate
First run: 2023-08-15T18:56:11.202060
Last run: 2023-08-17T13:29:29.969779

RUN ID: 2023-08-17T13:29:29.969779

|   Round # | Host                | RUNTIME   | ENERGY     | CPU_POWER   | CPU_UTIL   | GPU_POWER   | GPU_MEM    | DRAM_POWER   | MEM_UTIL   |
|         0 | hkn0432.localdomain | 995.967 s | 960.506 kJ | 231.819 W   | 3.240 %    | 702.327 W   | 55.258 GB  | 29.315 W     | 0.062 %    |
|         0 | hkn0436.localdomain | 994.847 s | 960.469 kJ | 235.162 W   | 3.239 %    | 701.588 W   | 56.934 GB  | 27.830 W     | 0.061 %    |
|         0 | All                 | 995.967 s | 1.921 MJ   | 466.981 W   | 3.240 %    | 1.404 kW    | 112.192 GB | 57.145 W     | 0.061 %    |

The application has been run 7 times. Throught its runtime, it has used 3.128 kWh, released a total of 1.307 kgCO2e into the atmosphere, and you paid 1.02 € in electricity for it.

Perun will keep track of the energy of your application over multiple runs.

Function Monitoring

Using a function decorator, information can be calculated about the runtime, power draw and component utilization while the function is executing.

import time
from perun import monitor

def main(n: int):

After running the script with perun monitor, the text report will add information about the monitored functions.

Monitored Functions

|   Round # | Function                    |   Avg Calls / Rank | Avg Runtime     | Avg Power        | Avg CPU Util   | Avg GPU Mem Util   |
|         0 | main                        |                  1 | 993.323±0.587 s | 964.732±0.499 W  | 3.244±0.003 %  | 35.091±0.526 %     |
|         0 | prepare_train_features      |                 88 | 0.383±0.048 s   | 262.305±19.251 W | 4.541±0.320 %  | 3.937±0.013 %      |
|         0 | prepare_validation_features |                 11 | 0.372±0.079 s   | 272.161±19.404 W | 4.524±0.225 %  | 4.490±0.907 %      |


Perun is compatible with MPI applications that make use of mpi4py, and requires changes in the code or in the perun configuration. Simply replace the python command with perun monitor.

mpirun -n 8 perun monitor path/to/your/


To get more information, check out our docs page.

Citing perun

If you found perun usefull, please consider citing the conference paper:

  • Gutiérrez Hermosillo Muriedas, J.P., Flügel, K., Debus, C., Obermaier, H., Streit, A., Götz, M.: perun: Benchmarking Energy Consumption of High-Performance Computing Applications. In: Cano, J., Dikaiakos, M.D., Papadopoulos, G.A., Pericàs, M., and Sakellariou, R. (eds.) Euro-Par 2023: Parallel Processing. pp. 17–31. Springer Nature Switzerland, Cham (2023).
  author="Guti{\'e}rrez Hermosillo Muriedas, Juan Pedro
  and Fl{\"u}gel, Katharina
  and Debus, Charlotte
  and Obermaier, Holger
  and Streit, Achim
  and G{\"o}tz, Markus",
  editor="Cano, Jos{\'e}
  and Dikaiakos, Marios D.
  and Papadopoulos, George A.
  and Peric{\`a}s, Miquel
  and Sakellariou, Rizos",
  title="perun: Benchmarking Energy Consumption of High-Performance Computing Applications",
  booktitle="Euro-Par 2023: Parallel Processing",
  publisher="Springer Nature Switzerland",
  abstract="Looking closely at the Top500 list of high-performance computers (HPC) in the world, it becomes clear that computing power is not the only number that has been growing in the last three decades. The amount of power required to operate such massive computing machines has been steadily increasing, earning HPC users a higher than usual carbon footprint. While the problem is well known in academia, the exact energy requirements of hardware, software and how to optimize it are hard to quantify. To tackle this issue, we need tools to understand the software and its relationship with power consumption in today's high performance computers. With that in mind, we present perun, a Python package and command line interface to measure energy consumption based on hardware performance counters and selected physical measurement sensors. This enables accurate energy measurements on various scales of computing, from a single laptop to an MPI-distributed HPC application. We include an analysis of the discrepancies between these sensor readings and hardware performance counters, with particular focus on the power draw of the usually overlooked non-compute components such as memory. One of our major insights is their significant share of the total energy consumption. We have equally analyzed the runtime and energy overhead perun generates when monitoring common HPC applications, and found it to be minimal. Finally, an analysis on the accuracy of different measuring methodologies when applied at large scales is presented.",
Logo of perun
Programming language
  • Python 100%
  • BSD-3-Clause
</>Source code

Participating organisations

Karlsruhe Institute of Technology (KIT)


Juan Pedro Gutiérrez Hermosillo Muriedas
Karlsruhe Institut für Technologie