leezu commented on a change in pull request #17297: Fix NCCL Cmake autodetect issue URL: https://github.com/apache/incubator-mxnet/pull/17297#discussion_r367382186
########## File path: cmake/Modules/FindNCCL.cmake ########## @@ -33,6 +33,23 @@ set(NCCL_ROOT_DIR "" CACHE PATH "Folder contains NVIDIA NCCL") +# first check in the /usr/local/cuda before other paths Review comment: Quoting from https://cmake.org/cmake/help/latest/command/find_path.html > This command is used to find a directory containing the named file. A cache entry named by `<VAR>` is created to store the result of this command. If the file in a directory is found the result is stored in the variable and the search will not be repeated unless the variable is cleared. If nothing is found, the result will be `<VAR>-NOTFOUND`, and the search will be attempted again the next time find_path is invoked with the same variable. Thus if there is some `nccl.h` at `/usr/local/cuda` but the user specifies `NCCL_ROOT_DIR=/home/ubuntu/myversionofnccl`, the `/usr/local/cuda` is wrongly used? Or do I misunderstand the doc? Btw, as per https://cmake.org/cmake/help/latest/policy/CMP0074.html `NCCL_ROOT_DIR` should probably be called `NCCL_ROOT` (or `NCCL_ROOT` should be added in addition to `NCCL_ROOT_DIR`). ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
