NVIDIA Deep Learning NCCL Documentation
Release Notes (PDF) - v2.21.5 - Last updated June 18, 2024

NCCL Release 2.12.12

This is the NCCL 2.12.12 release notes. For previous NCCL release notes, refer to the NCCL Archives.


NCCL 2.12.12 has been tested with the following:

Key Features and Enhancements

This NCCL release includes the following key features and enhancements.

  • Improved allreduce performance when you have more than one network interface per GPU and you need to use PXN to close rings.

  • Added P2P_DIRECT_DISABLE parameter to disable direct access to pointers within a process.

  • Added support for PCI Gen5 on 5.4 kernels.

Fixed Issues

The following issues have been resolved in NCCL 2.12.12:
  • Fixed hang on cubemesh topologies.

  • Fixed random crash in init due to uninitialized struct.

  • Fixed crash when setting NCCL_SET_THREAD_NAME.

Updating the GPG Repository Key

To best ensure the security and reliability of our RPM and Debian package repositories, NVIDIA is updating and rotating the signing keys used by apt, dnf/yum, and zypper package managers beginning on April 27, 2022. Failure to update your repository signing keys will result in package management errors when attempting to access or install NCCL packages. To ensure continued access to the latest NCCL release, please follow the updated NCCL installation guide.