An extensible vendor-neutral library for exposing power and performance monitoring and control capabilities of low-level hardware knobs.


Variorum is an extensible library for exposing monitor and control capabilities of low-level hardware knobs. Variorum provides vendor-neutral APIs such that the user can query or control hardware knobs without needing to know the underlying vendor’s implementation. These APIs enable HPC application developers to gain a better understanding of performance through various metrics for the devices contained within the node. Additionally, the APIs may enable system software to control hardware knobs to optimize for a particular goal.

Variorum focuses on ease of use and reduced integration burden in applications:

  • It includes examples which demonstrate how to use Variorum in a stand-alone program.
  • It includes an example performance analysis sampler that runs alongside the application.

Variorum Project Resources

Online Documentation

Github Source Repo

Issue Tracker


  • Peter Bailey
  • Stephanie Brink (LLNL)
  • Daniel Ellsworth
  • Aniruddha Marathe (LLNL)
  • Lauren Morita
  • Tapasya Patki (LLNL)
  • Barry Rountree (LLNL)
  • Kathleen Shoga (LLNL)
  • Scott Walker

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