Re: [cmake-developers] CUDA as a compiler instead FindCUDA?
On Sat, Jan 17, 2015 at 8:13 AM, Adam Strzelecki o...@java.pl wrote: 1. Support for dependency scanning. If I change a header included by file.cu I want file.cu to be recompiled. This is easy for makefiles, hard for anything else. .cu is superset of C++ so it should be pretty easy to get dependency scanning working same as for regular .cpp/.h files using CMake facilities. CMake doesn't support dependency scanning for Visual Studio. 2. In the past there have been bugs with nvcc, such as leaving a partially written output file during generation that failed, that FindCUDA has worked around. I don't see why we should care about that? If they still exist isn't it what NVIDIA partner bug report site is for? It may not be my fault, but it's my problem. If I can correct for problems and help others not have to deal with those same problems, I'm going to do that. We all have to deal with imperfect tools, and not all of us can wait for 1-2 years for bugs to be fixed. 3. Host flags generally need to be propagated to the CUDA flags (I'll admit that this support in FindCUDA isn't perfect). You mean user-defined preprocessor definitions or compiler flags? Host compiler flags are picked up by nvcc from host compiler itself. Aside of that, CMake will insert -D definitions as well to any extra compiler. So you may only want to wrap CMAKE_CXX_FLAGS into CMAKE_CUDACXX_FLAGS using -Xcompiler which can be tricky, but I believe we can workaround that somehow. 4. How do you support other targets besides cubin (obj), such as PTX? For what purpose? Debugging? CUDA supports two usage APIs. The runtime API that is used when you compile your code to object files, and the driver API that compiles to PTX or CUBIN and then loads that code into the driver directly. FindCUDA supports both. 5. How would separable compilation work? Especially since you can't easily replace the linker. Correct me if I am wrong, but we will still use platform linker. You can't use the platform linker for separable compilation unless you also produce intermediate linkage files. In order to produce intermediate linkage files you need all the object files compiled with separable linking to be run through another tool that produces this intermedate link file that will also need to be linked into the executable module. 6. If you support PTX, can you use the output as input for other custom commands (I like to encode the PTX into strings compiled into C++ files using bin2c from CUDA). Again can you please elaborate more why would you like to handle PTX yourself if CUDA does it for you, i.e.: nvcc -arch sm_30 - makes .o contain native device code nvcc -arch compute_30 - makes .o contain ptx code compiled later by the driver itself This sounds like some custom behavior. See my comment above regarding the driver versus runtime CUDA API. Yes it is different behavior, but I was able to accommodate both compilation models with the same tool. I would love for what you propose to work for both compilation modes, so if it is possible I would like to design it in. Otherwise it can't be a complete replacement for FindCUDA. James -- Powered by www.kitware.com Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Kitware offers various services to support the CMake community. For more information on each offering, please visit: CMake Support: http://cmake.org/cmake/help/support.html CMake Consulting: http://cmake.org/cmake/help/consulting.html CMake Training Courses: http://cmake.org/cmake/help/training.html Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Follow this link to subscribe/unsubscribe: http://public.kitware.com/mailman/listinfo/cmake-developers
Re: [cmake-developers] CUDA as a compiler instead FindCUDA?
On 01/16/2015 06:54 AM, Adam Strzelecki wrote: Hi. It makes me curious why CUDA support is not just implemented as compiler via proper CMakeDetermineCUDACompiler I don't think there is any reason besides no one doing it yet. is CMake open to accept patch that will make CUDA support via new compiler definition? Yes! Does CUDA distinguish between C and C++? Should there be separate CUDAC and CUDACXX languages? Does Visual Studio or Xcode have any builtin CUDA support, perhaps via a plugin? This will affect how the corresponding generators need to handle the language. Without native support then they will have to generate custom commands to build the languages. -Brad -- Powered by www.kitware.com Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Kitware offers various services to support the CMake community. For more information on each offering, please visit: CMake Support: http://cmake.org/cmake/help/support.html CMake Consulting: http://cmake.org/cmake/help/consulting.html CMake Training Courses: http://cmake.org/cmake/help/training.html Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Follow this link to subscribe/unsubscribe: http://public.kitware.com/mailman/listinfo/cmake-developers
Re: [cmake-developers] CUDA as a compiler instead FindCUDA?
On Fri, Jan 16, 2015 at 6:46 AM, Brad King brad.k...@kitware.com wrote: On 01/16/2015 06:54 AM, Adam Strzelecki wrote: Hi. It makes me curious why CUDA support is not just implemented as compiler via proper CMakeDetermineCUDACompiler I don't think there is any reason besides no one doing it yet. Whenever someone brings this up I want to make sure these features get considered. 1. Support for dependency scanning. If I change a header included by file.cu I want file.cu to be recompiled. This is easy for makefiles, hard for anything else. 2. In the past there have been bugs with nvcc, such as leaving a partially written output file during generation that failed, that FindCUDA has worked around. 3. Host flags generally need to be propagated to the CUDA flags (I'll admit that this support in FindCUDA isn't perfect). 4. How do you support other targets besides cubin (obj), such as PTX? 5. How would separable compilation work? Especially since you can't easily replace the linker. 6. If you support PTX, can you use the output as input for other custom commands (I like to encode the PTX into strings compiled into C++ files using bin2c from CUDA). is CMake open to accept patch that will make CUDA support via new compiler definition? Yes! Does CUDA distinguish between C and C++? Should there be separate CUDAC and CUDACXX languages? No. All CUDA code is C++ code as of 3-4 years ago. I wouldn't attempt to add support for really old versions of CUDA anyway. Does Visual Studio or Xcode have any builtin CUDA support, perhaps via a plugin? This will affect how the corresponding generators need to handle the language. Without native support then they will have to generate custom commands to build the languages. There are CUDA plugins (build rules for VS+MSbuild). These get updated for every version of CUDA. I'm not sure how the different versions live side by side, since I don't use them. James -- Powered by www.kitware.com Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Kitware offers various services to support the CMake community. For more information on each offering, please visit: CMake Support: http://cmake.org/cmake/help/support.html CMake Consulting: http://cmake.org/cmake/help/consulting.html CMake Training Courses: http://cmake.org/cmake/help/training.html Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Follow this link to subscribe/unsubscribe: http://public.kitware.com/mailman/listinfo/cmake-developers
