[petsc-dev] Makefile.user and CUDA

[Matthew Knepley]

On Wed, Oct 14, 2020 at 10:38 AM Patrick Sanan <patrick.sanan at gmail.com>
wrote:

> Here's a hack that seems to do what I want, but I don't think it's
> library-quality, as it extracts information from the "cuda" package in what
> seems like a brittle way:
>
> https://gitlab.com/petsc/petsc/-/merge_requests/3345
>

I think that is the same level of robustness as the rest of pkg-config

   Matt


> Am 13.10.2020 um 03:00 schrieb Jed Brown <jed at jedbrown.org>:
>
> Matthew Knepley <knepley at gmail.com> writes:
>
> On Mon, Oct 12, 2020 at 3:03 PM Patrick Sanan <patrick.sanan at gmail.com>
> wrote:
>
>
>
> Am 12.10.2020 um 20:11 schrieb Matthew Knepley <knepley at gmail.com>:
>
> On Mon, Oct 12, 2020 at 3:47 AM Patrick Sanan <patrick.sanan at gmail.com>
> wrote:
>
> I have a toy application code built on PETSc which needs to compile and
> link a .cu file.
>
> I'd love to be able to configure PETSc (with CUDA), and then use a
> modified version of share/petsc/Makefile.user to compile and link my code,
> using a consistent set of compilers, libraries, and flags.  Makefile.user
> uses petsc.pc (via pkg-config) and implicit GNU make rules to do almost
> everything for you for C, C++, and Fortran.
>
> However, I don't think it currently supports CUDA, and I'm not familiar
> enough with BuildSystem or pkg-config to quickly add support myself, so I
> resort to the "old" way, including things like this in my Makefile:
>
>
> Okay, here is where the pkgconf file gets generated, and in fact where the
> language sections are
>
>
> https://gitlab.com/petsc/petsc/-/blob/master/config/PETSc/Configure.py#L161
>
> I think you can just put a "CUDA" section in. I do not know what names to
> use, so I have not done it.
>
>
> That's where I got stuck as well :D
>
> I can follow the pattern to get the compiler (CUDAC) and some of the
> flags, but that doesn't seem to have all the information that CUDAC,
> CUDAC_FLAGS, CUDA_INCLUDE, and CUDA_LIB provide in petscvariables.
>
>
> I can dig around and find all these for you.
>
>
> Naively I would assume I'd need to dig around to figure out how those
> variables are populated, and get the same info into petsc.pc
>
> But, I worry that I'm misunderstanding fundamentals about pkg-config and
> how it is supposed to work. Am I free to put whatever fields I want in
> there, or is there some authority on what's "standard"?
>
>
> I do not understand anything about pkg-config (and think it is a
> fundamentally misguided mechanism). Jed, how should CUDA work with this?
>
>
> I have no experience, but here are some examples.  I think the caller is
> responsible for using nvcc if you have *.cu source.
>
> $ cat /usr/lib/pkgconfig/cublas.pc
> cudaroot=/opt/cuda
> libdir=${cudaroot}/targets/x86_64-linux/lib
> includedir=${cudaroot}/targets/x86_64-linux/include
>
> Name: cublas
> Description: CUDA BLAS Library
> Version: 11.0
> Libs: -L${libdir} -lcublas
> Cflags: -I${includedir}
>
>
> $ cat /usr/lib/pkgconfig/nvrtc.pc
> cudaroot=/opt/cuda
> libdir=${cudaroot}/targets/x86_64-linux/lib
> includedir=${cudaroot}/targets/x86_64-linux/include
>
> Name: nvrtc
> Description: A runtime compilation library for CUDA C++
> Version: 11.0
> Libs: -L${libdir} -lnvrtc
> Cflags: -I${includedir}
>
>
>

-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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