Intel® oneAPI Collective Communications Library (oneCCL) Developer Guide and Reference
ID
772609
Date
6/30/2025
Public
Enabling OFI/verbs/dmabuf Support
oneCCL provides experimental support for data transfers between Intel GPU memory and NIC using Linux dmabuf, which is exposed through OFI API for verbs provider.
Requirements
Linux kernel version >= 5.12
RDMA core version >= 34.0
level-zero-devel package
Usage
oneCCL, OFI and OFI/verbs from Intel® oneAPI Base Toolkit support device memory transfers. Refer to Run instructions for usage.
If you want to build software components from sources, refer to Build instructions.
Build instructions
OFI
git clone --single-branch --branch v1.13.2 https://github.com/ofiwg/libfabric.git
cd libfabric
./autogen.sh
./configure --prefix=<ofi_install_dir> --enable-verbs=<rdma_core_install_dir> --with-ze=<level_zero_install_dir> --enable-ze-dlopen=yes
make -j install
NOTE:
You may also get OFI release package directly from here. No need to run autogen.sh if using the release package.
oneCCL
cmake -DCMAKE_INSTALL_PREFIX=<ccl_install_dir> -DLIBFABRIC_DIR=<ofi_install_dir> -DCMAKE_C_COMPILER=icx -DCMAKE_CXX_COMPILER=icpx -DCOMPUTE_BACKEND=dpcpp -DENABLE_OFI_HMEM=1 ..
make -j installRun instructions
Set the environment. See Get Started Guide.
Run allreduce test with ring algorithm and SYCL USM device buffers:
export CCL_ATL_TRANSPORT=ofi export CCL_ATL_HMEM=1 export CCL_ALLREDUCE=ring export FI_PROVIDER=verbs mpiexec -n 2 <ccl_install_dir>/examples/sycl/sycl_allreduce_usm_test gpu device