TOPO: resolve NVML fabric symbols lazily#1305
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@Sergei-Lebedev @ikryukov codex solution - I check it with the above tests, before/after PR, if you get a chance and have pointers how to guide it for a better fix if needed - let me know |
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Juee14Desai
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| return handle ? handle : RTLD_DEFAULT; |
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If we fall through to RTLD_DEFAULT, it might be worth logging a ucc_debug() message so it's visible in debug output that we couldn't obtain a dedicated NVML handle.
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Signed-off-by: Tomislav Janjusic <tomislavj@nvidia.com>
Signed-off-by: Tomislav Janjusic <tomislavj@nvidia.com>
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What
This PR avoids a hard runtime dependency on newer NVML fabric-info symbols in the CUDA sysinfo component.
Specifically,
nvmlDeviceGetGpuFabricInfoVand the legacynvmlDeviceGetGpuFabricInfopath are now resolved lazily withdlsym()before use.Why ?
HPC SDK users can build UCC/HPC-X with newer CUDA/NVML headers but run on systems with older NVIDIA drivers. In that case,
libucc_sysinfo_cuda.socould fail to load with:undefined symbol: nvmlDeviceGetGpuFabricInfoVThat symbol is only available in newer
libnvidia-ml.so.1versions, so directly referencing it raises the effective runtime driver requirement even when fabric metadata is optional.How ?
The CUDA sysinfo fabric query now uses a small runtime resolver for optional NVML fabric APIs. If the versioned fabric-info symbol is available, UCC uses it and preserves partition ID support. If it is unavailable, UCC falls back to the legacy fabric-info API when present. If neither symbol exists, fabric metadata remains unset and UCC continues without failing library load.
Testing
Tested before/after with CUDA 12.9.1 and NVML 555 at build time, then switched runtime NVML to R525.60.13.
Before this PR:
config.hdefinedHAVE_NVML_GPU_FABRIC_INFO_V.readelf -Ws libucc_sysinfo_cuda.so | grep nvmlDeviceGetGpuFabricInfoshowed an undefined relocation fornvmlDeviceGetGpuFabricInfoV.ldd -r libucc_sysinfo_cuda.sofailed with:undefined symbol: nvmlDeviceGetGpuFabricInfoVAfter this PR:
readelfandnm -Dshow no dynamic dependency onnvmlDeviceGetGpuFabricInfo*.ldd -r libucc_sysinfo_cuda.soreports no undefined fabric-info symbols.