Replace use of FindCUDA with native CMake CUDA support.

[robinson96]

Meant to be a drop in replacement for FindCUDA. The only change I had to do do my host-config was to drop an explicit definition of -std=c++, as the native CMake puts it in there the right way and nvcc complains if you define it twice.

[cyrush]

If this works for your use cases, I think its safe to transition. What is the minimum version of CMake this will require - 3.9 or 3.10? We should make a note in the docs about that.

[davidbeckingsale]

How does this handle stuff that only needs the CUDA runtime library?

[robinson96]

@cyrush : I'm using 3.9.2 - have not tested with earlier versions.
@davidbeckingsale : I think I have something that in theory should exercise that, but will confirm for you. Might be nice if you had an existing project for me to clone and test this with.

[white238]

Please remove support for as many FindCUDA variables as possible. I would like this as close to normal CMake conventions as possible. This reduces the amount of upkeep we need to support going forward. This applies to CUDA_BIN_PATH, CUDA_HOST_COMPILER, and CUDA_NVCC_FLAGS.

[robinson96]

Regarding CUDA_SEPARABLE_COMPILATION - I think it's best practice to do this in general, I don't think there is harm to doing separable compilation but it's certainly a pitfall folks can encounter. Should I just do that by default for the sake of killing the CUDA_SEPARABLE_COMPILATION flag?

[cyrush]

I think users can easily control globally withCMAKE_CUDA_SEPARABLE_COMPILATION -- we don't have any per-target options for separable compilation exposed in the macro sig -- so I think you can at least pull it out from this macro.

[davidbeckingsale]

I want to verify that we still have the "cuda_runtime" dependency working

[white238]

The existing CUDA examples will need to be switched as well as documentation updated. I can help with any of that if you would like.

[kennyweiss]

Thanks @robinson96.

Have you tested this update against blt's cuda examples? Please ensure that the cuda-based tests and examples pass under this PR, and update the host-config for ray as necessary (in the host-configs directory).

Note: The old host-config for ray was broken the last time I checked (see #146).

[robinson96]

@davidbeckingsale : we are still using the CMAKE built in FindCUDA to set all the libraries and paths necessary for the cuda_runtime target. I've verified that that behavior is reasonable.

[davidbeckingsale]

That’s fine with me. Is everyone okay with the require CMake version getting bumped up?

[robinson96]

rzmanta32{probinso}24: make test
Running tests...
Test project /g/g18/probinso/git/blt/tests/internal/build
Start 1: t_example_smoke
1/7 Test #1: t_example_smoke .................. Passed 0.01 sec
Start 2: t_header_only_smoke
2/7 Test #2: t_header_only_smoke .............. Passed 0.01 sec
Start 3: blt_gtest_smoke
3/7 Test #3: blt_gtest_smoke .................. Passed 0.01 sec
Start 4: blt_mpi_smoke
4/7 Test #4: blt_mpi_smoke .................... Passed 0.95 sec
Start 5: blt_cuda_smoke
5/7 Test #5: blt_cuda_smoke ................... Passed 0.13 sec
Start 6: blt_cuda_runtime_smoke
6/7 Test #6: blt_cuda_runtime_smoke ........... Passed 0.03 sec
Start 7: t_cuda_device_call_from_kernel
7/7 Test #7: t_cuda_device_call_from_kernel ... Passed 0.12 sec

100% tests passed, 0 tests failed out of 7

Total Test time (real) = 1.31 sec
rzmanta32{probinso}25:

[rhornung67]

@davidbeckingsale and @robinson96 you may want to check with @ajkunen about CMake versions. I recall him telling me that he had issues with some later versions.

[cyrush]

@rhornung67 thanks for the warning, that rings with what I fear.
I am hoping we can stick with 3.9.x.

[rhornung67]

@cyrush my purpose is to ring your fears....

[ajkunen]

I was having linking issues when using cmake 3.9.2, and had to back out to an early version. I haven’t tried to figure out why… nor do I have the time. It may be that we’re doing something stupid.

…

-Adam From: Cyrus Harrison <notifications@github.com> Reply-To: LLNL/blt <reply@reply.github.com> Date: Wednesday, May 16, 2018 at 1:10 PM To: LLNL/blt <blt@noreply.github.com> Cc: Adam Kunen <kunen1@llnl.gov>, Mention <mention@noreply.github.com> Subject: Re: [LLNL/blt] Replace use of FindCUDA with native CMake CUDA support. (#154) @rhornung67<https://github.com/rhornung67> thanks for the warning, that rings with what I fear. I am hoping we can stick with 3.9.x. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub<#154 (comment)>, or mute the thread<https://github.com/notifications/unsubscribe-auth/ARGiBO-QXibL842f8HSm2y4pDzjYTdZoks5tzIeQgaJpZM4T_7Y->.

[davidbeckingsale]

Hmm, I'm sure you were doing something stupid 😄 did you ever try with a version > 3.9.2?

[ajkunen]

Nope

…

-Adam From: David Beckingsale <notifications@github.com> Reply-To: LLNL/blt <reply@reply.github.com> Date: Wednesday, May 16, 2018 at 3:13 PM To: LLNL/blt <blt@noreply.github.com> Cc: Adam Kunen <kunen1@llnl.gov>, Mention <mention@noreply.github.com> Subject: Re: [LLNL/blt] Replace use of FindCUDA with native CMake CUDA support. (#154) Hmm, I'm sure you were doing something stupid 😄 did you ever try with a version > 3.9.2? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub<#154 (comment)>, or mute the thread<https://github.com/notifications/unsubscribe-auth/ARGiBPwf_hefubRGxyYLAnkvB75k-sBOks5tzKRmgaJpZM4T_7Y->.

[kennyweiss]

Thanks for fixing the host-configs @robinson96.
Please close #146 when you merge.

[robinson96]

FWIW: the surface test I ran under this stuff was using cmake 3.8. That doesn't exercise the LINK_WITH_NVCC stuff, but it does exercise the SEPARABLE_COMPILATION.