Fixes for no-IB systems #667
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Pull Request Overview
This PR adds the ability to optionally disable InfiniBand (IB) support in MSCCL++ through a new CMake option MSCCLPP_USE_IB. The changes ensure that the codebase can compile and tests can run correctly when IB support is not available.
Key changes:
- Introduced
MSCCLPP_USE_IBCMake option to control InfiniBand compilation - Updated test code to conditionally skip IB-specific tests when not compiled with IB support
- Modified build configuration to use
MSCCLPP_USE_IBinstead ofIBVERBS_FOUND
Reviewed Changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.
Show a summary per file
| File | Description |
|---|---|
| CMakeLists.txt | Added MSCCLPP_USE_IB option and conditional IB package finding with error handling |
| test/CMakeLists.txt | Updated to use MSCCLPP_USE_IB flag instead of IBVERBS_FOUND |
| test/perf/CMakeLists.txt | Updated to use MSCCLPP_USE_IB flag instead of IBVERBS_FOUND |
| test/mp_unit/port_channel_tests.cu | Added conditional compilation guards for IB-specific tests and disabled IB in non-IB tests |
| test/mp_unit/memory_channel_tests.cu | Removed IB transport usage from MemoryChannel tests |
| test/mp_unit/ib_tests.cu | Added early skip for IB tests when not compiled with IB support |
| test/mp_unit/communicator_tests.cu | Added conditional compilation for IB transport usage |
| src/ib.cc | Moved nvidia_peermem check to registration time and marked helper function as maybe_unused |
| docs/quickstart.md | Documented the new MSCCLPP_USE_IB CMake option |
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Updated OS requirements and added information about GPUDirect RDMA support.
Binyang2014
approved these changes
Oct 29, 2025
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MSCCLPP_USE_IBthat explicitly specifies IB on/offnvidia-peermemcheck; no need for DMABUF supported systemsmp_unit_teststo skip all IB tests when built with-DMSCCLPP_USE_IB=OFF