OpenMP in LLVM Multi-company Telecom Meeting Minutes July15th

Runtimes OpenMP
1

Next Meeting : July 29th

  • Opens
  • global variables marked with declare target used in map clause

map clause of global declare targets are ignored. Ye Lou has filed a bug here https://bugs.llvm.org/show_bug.cgi?id=46012

We agreed this is a bug in clang, the map should be generated with OMP_TGT_MAPTYPE_PTR_AND_OBJ so if memory is allocated the global pointer can be updated.

  • pragma openmp tile support

Micheal wanted to know the review status of openmp tile support https://reviews.llvm.org/D76342

Alexey has a redesign which may requires addition change to merge into Michael’s patch https://reviews.llvm.org/D83261

  • OpenmpD

AMD has group of people working on it.

Taken the work done by Joachim Protze and other applied to their base

Would like to check this into llvm org.

Nota huge amount of changes. Most of the changes is in openmpd plugin. Some changes in openmp and libomptarget runtime.

Plan is to discuss the next steps in one of the upcoming meetings

  • Generalize CGOpenMPRuntime to support many GPU targets.

Patch can be found here https://reviews.llvm.org/D83723

LLVM11 branching has happened today. Should we cherry pick into 11.

Johannes recommended to target it for 12.

  • Status of OpenMP version switch to 50

  • Patch to remove versioning to test OpenMP 5.0 which is the default is here https://reviews.llvm.org/D82575.

  • About 67 tests had version 4.5 hardcoded. Saiyedul has a patch to change hardcoded version 4.5. https://reviews.llvm.org/D83863

  • Removing version 4.5 would not be testing changes were made just for 4.5, since it is still supported

  • Suggestion was to have both 4.5 and default testing so unexpected behavior can be caught…

  • Only use versioning if testing for a specific divergent in the spec.

  • Consider test generation kit for auto generation https://reviews.llvm.org/D83004

  • Fat static libraries

  • unbundle archive in review. https://reviews.llvm.org/D80816 .

  • Tool chain change to use the archive is progress…

  • Async Support

  • Johannes speaking on behalf of Sheilei: Performance experiments were done. Hope to present the data next meeting.

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  • Mapper

  • George has lIbomptarget patch ready for commit.

  • Clang was missing support for default mapper which Lingda had agreed to add.

  • Informal meetings

  • Have more people participating/working and we usually not able to cover all the topics, do we need to have more meetings?

  • Suggestion was to have meeting every week instead of every other week, with one week being the regular meeting discussion at a high level and the other week a deep dive.

  • The deep dive can be walking through fabricator review, feature list etc.

  • Johannes volunteered to host deep dive meeting…

  • Need review link in the agenda.

  • Greg wanted the review link available before the meeting

  • This involves lots of coordination. He is ok with posting in the chat during the meeting.

  • Ye lou wanted some place to put all this info.

  • The features are tracked here https://clang.llvm.org/docs/OpenMPSupport.html

  • Maybe add a section at bottom to track things other main features.

Roll Call :

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