Portable Hardware Locality (hwloc)

The Portable Hardware Locality (hwloc) software package provides a portable abstraction (across OS, versions, architectures, ...) of the hierarchical topology of modern architectures, including NUMA memory nodes, sockets, shared caches, cores and simultaneous multithreading. It also gathers various system attributes such as cache and memory information. It primarily aims at helping applications with gathering information about modern computing hardware so as to exploit it accordingly and efficiently.

hwloc may display the topology in multiple convenient formats (see v0.9.2 examples). It also offers a powerful programming interface to gather information about the hardware, bind processes, and much more.

More details are available in the Documentation (in both PDF and HTML). The documentation for each version contains examples of outputs and an API interface example (these links are for v0.9.2).

Questions and bugs

Questions, comments, and bugs should be sent to hwloc mailing lists.

Also be sure to see the hwloc wiki and bug tracking system.

History / credits

hwloc is the evolution and merger of the libtopology project and the Portable Linux Processor Affinity (PLPA) project. Because of functional and idological overlap, these two code bases and ideas were merged and released under the name "hwloc" as an Open MPI sub-project.

libtopology was initially developed by the INRIA Runtime Team-Project (headed by Raymond Namyst). PLPA was initially developed by the Open MPI development team as a sub-project. Both are now deprecated in favor of hwloc, which is distributed here as an Open MPI sub-project.