Adios2 doesn't check for MPI Server/Client Support if not using MPICH

[RemiLacroix-IDRIS]

Hello,

Looking at the code, Adios2 doesn't check for MPI Server/Client Support if not using MPICH:

ADIOS2/cmake/DetectOptions.cmake

Lines 463 to 492 in 8cd2d94

	if(ADIOS2_HAVE_MPI AND NOT "${ADIOS2_SST_HAVE_MPI_DP}")
	set(CMAKE_REQUIRED_LIBRARIES "MPI::MPI_C;Threads::Threads")
	include(CheckCXXSourceRuns)
	check_cxx_source_runs([=[
	#include <chrono>
	#include <future>
	#include <mpi.h>
	#include <thread>
	#include <stdlib.h>
	#if !defined(MPICH)
	#error "MPICH is the only supported library"
	#endif
	int main()
	{
	// Timeout after 5 second
	auto task = std::async(std::launch::async, []() {
	std::this_thread::sleep_for(std::chrono::seconds(5));
	exit(EXIT_FAILURE);
	});
	char* port_name = new char[MPI_MAX_PORT_NAME];
	MPI_Init_thread(NULL, NULL, MPI_THREAD_MULTIPLE, NULL);
	MPI_Open_port(MPI_INFO_NULL, port_name);
	MPI_Close_port(port_name);
	MPI_Finalize();
	exit(EXIT_SUCCESS);
	}]=]
	ADIOS2_HAVE_MPI_CLIENT_SERVER)

Is this on purpose? Shouldn't newish version of OpenMPI work too?

Best regards,
Rémi

[eisenhauer]

Maybe? Trying it and letting us know would expedite acceptance...

@vicentebolea Any idea?

[vicentebolea]

OpenMPI support of MPI_connect/accept has been flaky if not broken in the past: open-mpi/ompi#3458 open-mpi/ompi#6446. We have observed that with particular backends selections and newer versions it does work, however, we have had a large amount of users complaining that the mpi dataset was not working in their builds with ompi, for that reason we decided to disable it by default when using ompi.

You can force the check to be TRUE by setting the ADIOS2_HAVE_MPI_CLIENT_SERVER variable to ON/TRUE/1.