Programming Guide


Intel oneAPI Collective Communications Library (oneCCL)

Intel oneAPI Collective Communications Library (oneCCL) is a scalable and high-performance communication library for Deep Learning (DL) and Machine Learning (ML) workloads. It develops the ideas that originated in Intel® Machine Learning Scaling Library and expands the design and API to encompass new features and use cases.
oneCCL features include:
  • Built on top of lower-level communication middleware – MPI and libfabrics
  • Optimized to drive scalability of communication patterns by enabling the productive trade-off of compute for communication performance
  • Enables a set of DL-specific optimizations, such as prioritization, persistent operations, out of order execution, etc.
  • DPC++-aware API to run across various hardware targets, such as CPUs and GPUs
  • Works across various interconnects: Intel® Omni-Path Architecture (Intel® OPA), InfiniBand*, and Ethernet

Product and Performance Information


Performance varies by use, configuration and other factors. Learn more at