[Openmp-dev] Offloading API

[Sergey Ostanevich via Openmp-dev]

Herve,

I can't get the idea to associate an identifier with a variable. Consider
you have multiple threads running on host and each thread has its own
private copy of a variable. How would you name it in Clang then? How would
you change naming in case number of threads is defined dynamicly?
I bet that this should be an offload library duty to associate the host
address of a variable with the (file?) identifier. Then you will reuse the
same identifier while mapping is alive and will replace it with the new one
as soon as mapping will be re-created anew.

Regards,
Sergos


On Fri, Oct 9, 2015 at 6:44 PM, Hervé Yviquel <openmp-dev at lists.llvm.org>
wrote:

> Hi all,
>
> Some of my colleagues and I are currently developing the infrastructure
> for adding a new device, the cloud, to the list of available targets.
> Considering the cloud as a device requires few changes to the API of the
> offloading library (libomptarget). Indeed, our cloud device handles
> offloading data thanks to files instead of values within an address space.
> To do so, we had to associate each offloaded variables with a unique
> identifier. Those identifiers are assigned by Clang to each variable, then
> transmitted to libomptarget as an additional argument of the offloading
> function "__tgt_target". In case of pointer addresses that are not
> generated by Clang, the special identifier "-1" is attributed. This allows
> us to easily skip the offloading of these addresses that our device doesn't
> use.
>
> You can find attached the patches including the needed modifications both
> for Clang and libomptarget (based on the repositories of
> https://github.com/clang-omp/). If needed, I can make a push request
> directly in github.
>
> Let's us precise that we plan to open source all this work and to submit
> patches to the upstream Clang/OpenMP repositories when it will be mature
> enough. Additionally to simplify future integrations, those API changes can
> be helpful for any exotic offloading target. That's why we propose to
> integrate them directly.
>
> Regards,
> --
> Hervé Yviquel
> Postdoc researcher
> Instituto de Computação (IC) - UNICAMP
> http://people.irisa.fr/Herve.Yviquel/
>
>
>
>
> _______________________________________________
> Openmp-dev mailing list
> Openmp-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/openmp-dev
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/openmp-dev/attachments/20151015/3fde0a98/attachment.html>