energymon 0.0.2

Python bindings to native energymon libraries

EnergyMon Python Bindings

This project provides Python bindings to energymon libraries.

If using this project for other scientific works or publications, please reference:

• Connor Imes, Lars Bergstrom, and Henry Hoffmann. "A Portable Interface for Runtime Energy Monitoring". In: FSE. 2016. DOI: https://doi.org/10.1145/2950290.2983956

  [BibTex]

  @inproceedings{imes2016energymon,
    author = {Imes, Connor and Bergstrom, Lars and Hoffmann, Henry},
    title = {A Portable Interface for Runtime Energy Monitoring},
    year = {2016},
    isbn = {9781450342186},
    publisher = {Association for Computing Machinery},
    address = {New York, NY, USA},
    url = {https://doi.org/10.1145/2950290.2983956},
    doi = {10.1145/2950290.2983956},
    booktitle = {Proceedings of the 2016 24th ACM SIGSOFT International Symposium on Foundations of Software Engineering},
    pages = {968–974},
    numpages = {7},
    keywords = {portable energy measurement},
    location = {Seattle, WA, USA},
    series = {FSE 2016}
  }
  

Dependencies

The energymon libraries should be installed to the system and on the library search path (e.g., LD_LIBRARY_PATH on Linux/POSIX systems or DYLD_LIBRARY_PATH on macOS systems).

The latest energymon C libraries can be found at https://github.com/energymon/energymon.

Installing

Versioned releases of the energymon package are published in the Python Package Index and installable with pip:

pip install energymon

To install from source:

pip install .

Usage

The module exposes an energymon class, which is a binding to the energymon C struct.

While you may use the bindings directly, the module exposes some utilities to simplify usage, e.g., to load the library, "get" the energymon, handle pointers, convert data types, check for errors, and raise exceptions. For example, to use the energymon-default library:

from energymon import util

lib = util.load_energymon_library()
em = util.get_energymon(lib)
print(util.get_source(em))
util.init(em)
try:
    print(util.get_uj(em))
finally:
    util.finish(em)

Direct bindings

To directly use the energymon API, first load the library, create and "get" the struct to populate its function pointers, then initialize, do work, and cleanup when finished. For example:

from ctypes import CDLL, byref, create_string_buffer, sizeof, set_errno, get_errno
from ctypes.util import find_library
from energymon import energymon

# try to find the library by name:
lib_path = find_library('energymon-default')
if lib_path is None:
    # maybe fall back on a relative or absolute path
    lib_path = 'libenergymon-default.so'

lib = CDLL(lib_path, use_errno=True)
em = energymon()
if lib.energymon_get_default(byref(em)) != 0:
    # handle error...
    exit(1)

name = create_string_buffer(256)
if not em.fsource(name, sizeof(name)):
    # handle error
    exit(1)

print(name.value.decode())
if em.finit(byref(em)) != 0:
    # handle error
    exit(1)

set_errno(0)
uj = em.fread(byref(em))
if uj == 0 and get_errno() != 0:
    # handle error (but don't skip cleanup!)
    pass

if em.ffinish(byref(em)) != 0:
    # handle error
    exit(1)

Project Source

Find this and related project sources at the energymon organization on GitHub.
This project originates at: https://github.com/energymon/energymon-py

Bug reports and pull requests for bug fixes and enhancements are welcome.