---
name: "hwlocality_nvml"
section: "3"
platform: "linux"
package: "hwloc"
version: "2.15.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/hwlocality_nvml"
---

# hwlocality\_nvml(3)

Interoperability with the NVIDIA Management Library

## NAME

hwlocality\_nvml - Interoperability with the NVIDIA Management Library

## SYNOPSIS

### Functions

int **hwloc\_nvml\_get\_device\_cpuset** (**hwloc\_topology\_t** topology, nvmlDevice\_t device, **hwloc\_cpuset\_t** set)\
 **hwloc\_obj\_t** **hwloc\_nvml\_get\_device\_osdev\_by\_index** (**hwloc\_topology\_t** topology, unsigned idx)\
 **hwloc\_obj\_t** **hwloc\_nvml\_get\_device\_osdev** (**hwloc\_topology\_t** topology, nvmlDevice\_t device)\

## Detailed Description

This interface offers ways to retrieve topology information about devices managed by the NVIDIA Management Library (NVML).

## Function Documentation

### int hwloc\_nvml\_get\_device\_cpuset (hwloc\_topology\_t topology, nvmlDevice\_t device, hwloc\_cpuset\_t set) \[inline\]

Get the CPU set of processors that are physically close to NVML device device. Store in set the CPU-set describing the locality of the NVML device device.

Topology topology and device device must match the local machine. I/O devices detection and the NVML component are not needed in the topology.

The function only returns the locality of the device. If more information about the device is needed, OS objects should be used instead, see **hwloc\_nvml\_get\_device\_osdev()** and **hwloc\_nvml\_get\_device\_osdev\_by\_index()**.

This function is currently only implemented in a meaningful way for Linux; other systems will simply get the cpuset of the entire topology.

**Returns**

0 on success.

\-1 on error, for instance if device information could not be found.

### hwloc\_obj\_t hwloc\_nvml\_get\_device\_osdev (hwloc\_topology\_t topology, nvmlDevice\_t device) \[inline\]

Get the hwloc OS device object corresponding to NVML device device.

**Returns**

The hwloc OS device object that describes the given NVML device device.

NULL if none could be found.

Topology topology and device device must match the local machine. I/O devices detection and the NVML component must be enabled in the topology. If not, the locality of the object may still be found using **hwloc\_nvml\_get\_device\_cpuset()**.

**Note**

The corresponding hwloc PCI device may be found by looking at the result parent pointer (unless PCI devices are filtered out).

### hwloc\_obj\_t hwloc\_nvml\_get\_device\_osdev\_by\_index (hwloc\_topology\_t topology, unsigned idx) \[inline\]

Get the hwloc OS device object corresponding to the NVML device whose index is idx.

**Returns**

The hwloc OS device object describing the NVML device whose index is idx.

NULL if none could be found.

The topology topology does not necessarily have to match the current machine. For instance the topology may be an XML import of a remote host. I/O devices detection and the NVML component must be enabled in the topology.

**Note**

The corresponding PCI device object can be obtained by looking at the OS device parent object (unless PCI devices are filtered out).

## Author

Generated automatically by Doxygen for Hardware Locality (hwloc) from the source code.