Introduction to OpenMP offload: data movement

[lucaparisi91]

Base material at OpenMPTargetOffload.ppt

• Data transfers overview
• map directives ( to, from,tofrom, alloc, always )
• #pragma omp enter/exit/update data
• zero copy ( unified memory , managed memory )

[welucas2]

Useful sources:

• https://www.olcf.ornl.gov/wp-content/uploads/2021/08/ITOpenMPO_Day2.pdf
• https://www.openmp.org/wp-content/uploads/2021-10-20-Webinar-OpenMP-Offload-Programming-Introduction.pdf
• https://www.olcf.ornl.gov/wp-content/uploads/2018/02/SummitDev_OpenMP4.5-tutorial-jan17.pdf

A lot of this is drawn directly from the OpenMP specs at https://www.openmp.org/spec-html/5.2/openmpsu60.html, https://www.openmp.org/spec-html/5.1/openmpsu119.html.

[welucas2]

I think that's the initial version done and the copy on Sharepoint updated. I've covered map, structured and unstructured data clauses, and device pointers. I haven't covered omp declare target but could do if this is considered important. LIkewise for unified and shared memory. I feel these might be better in a later session, if they are to be covered; what's here already feels quite beefy and potentially a little overwhelming to newcomers.

[lucaparisi91]

Thanks @welucas2 . For unified memory I have added it to the advanced topics ( see #35 )