[petsc-dev] -with-kokkos-cuda-arch=AMPERE80 nonsense

[Mills, Richard Tran]

Hmm, OK, I found a table at

  https://sparta.sandia.gov/doc/accelerate_kokkos.html

and it tells me that "PASCAL60" refers to "NVIDIA Pascal generation CC 6.0 GPU" and "PASCAL61" refers to "NVIDIA Pascal generation CC 6.1 GPU". But I have no idea what those 6.0 vs 6.1 version numbers mean, and I can't seem to easily find any information from NVIDIA that connects anything in the output of "nvidia-smi -a" to these versions.

I think maybe what I want is an NVIDIA equivalent to Intel's ark.intel.com, which decodes the mysterious Intel version numbers to tell me what architectural features are present. But does anything like this exist for NVIDIA?

--Richard



On 4/5/21 1:10 PM, Mills, Richard Tran wrote:
You raise a good point, Barry. I've been completely mystified by what some of these names even mean. What does "PASCAL60" vs. "PASCAL61" even mean? Do you know of where this is even documented? I can't really find anything about it in the Kokkos documentation. The only thing I can really find is an issue or two about "hey, shouldn't our CMake stuff figure this out automatically" and then some posts about why it can't really do that. Not encouraging.

--Richard

On 4/3/21 8:42 PM, Barry Smith wrote:

  It would be very nice to NOT require PETSc users to provide this flag, how the heck will they know what it should be when we cannot automate it ourselves?

  Any ideas of how this can be determined based on the current system? NVIDIA does not help since these "advertising" names don't seem to trivially map to information you can get from a particular GPU when you logged into it. For example nvidia-smi doesn't use these names directly. Is there some mapping from nvidia-smi  to these names we could use? If we are serious about having a non-trivial number of users utilizing GPUs, which we need to be for future, we cannot have this absurd demands in our installation process.

  Barry

Does spack have some magic for this we could use?




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