STEllAR-GROUP
The new LCW (or MPIx) parcelport
The advanced MPI parcelport that can utilize the MPICH VCI and Continuation extensions.
The exact MPI implementation is wrapped in a thin wrapper layer (the Lightweight Communication Wrapper, or LCW). This wrapper layer provides an active message, send/recv, completion queue, and device abstraction on top of MPI (with/without extensions), GASNet-EX, and LCI.
The GASNet-EX backend of LCW cannot be used in HPX for now, as it lacks send/recv support.
Important CMake Variables:
HPX_WITH_PARCELPORT_LCW(defaultOFF): enable the LCW parcelport.HPX_WITH_FETCH_LCW(default:OFF): enable LCW autofetch. Important Runtime Variables:--hpx:ini=hpx.parcel.lcw.ndevices=<n>(default:2): the number of the LCW devices to use. Each LCW device will be mapped to an MPI communicator or an LCI device.
TODO:
- [x] Add CI.
- [x] Add documentation.
@hkaiser Do you have any suggestions on how I might resolve the GCC 15 errors? They seem to be related to the C++20 modules.
Also, the new parcelport can occasionally fail the tests.unit.modules.runtime_components.distributed.lcw.migrate_polymorphic_component test. Do you have thoughts on what might happen (e.g., does this test involve large metadata transfers)?
@hkaiser Do you have any suggestions on how I might resolve the GCC 15 errors? They seem to be related to the C++20 modules.
Also, the new parcelport can occasionally fail the
tests.unit.modules.runtime_components.distributed.lcw.migrate_polymorphic_componenttest. Do you have thoughts on what might happen (e.g., does this test involve large metadata transfers)?
The migration error is unrelated, we see it on other platforms occasionally as well. For the gcc15 errors (https://cdash.rostam.cct.lsu.edu/viewBuildError.php?buildid=33246), you simply missed to #include <cstdint>, possibly you will need to qualify the types (e.g. std::uint32_t).
Please ignore the strange CI problems on rostam (where no results are reported at all), we're working on fixing this.