Intel® oneAPI Programming Guide

Programming Guide

Contents

oneCCL Usage

Refer to the Intel oneAPI Collective Communications Library System Requirements for a full list of hardware and software dependencies, such as MPI and Intel oneAPI DPC++/C++ Compiler.
SYCL*-aware API is an optional feature of oneCCL. There is a choice between CPU and SYCL back ends when creating the oneCCL stream object.
  • For CPU backend: Specify
    ccl_stream_host
     as the first argument.
  • For SYCL backend: Specify
    ccl_stream_cpu
     or
    ccl_stream_gpu
     depending on the device type.
  • For collective operations that operate on the SYCL stream:
    • For C API, oneCCL expects communication buffers to be
      sycl::buffer
       objects casted to
      void*
      .
    • For C++ API, oneCCL expects communication buffers to be passed by reference.
Additional usage details are available from https://oneapi-src.github.io/oneCCL/.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.