From 1610f757aca30ec2228e6cb9286338264f032545 Mon Sep 17 00:00:00 2001 From: Christian Pfeiffer Date: Tue, 24 Oct 2017 16:14:14 +0200 Subject: FindMPI: Use physical cores for MPIEXEC_MAX_NUMPROCS Since commit v3.9.0-rc1~224^2~1 (FindMPI: MPIEXEC handling improvements, 2017-04-21) the `ProcessorCount` module is being used to initialize `MPIEXEC_MAX_NUMPROCS`. However, this leads to the logical cores being counted rather than the physical ones, and some MPI implementations like OpenMPI will error if mpiexec is called with that number. Switch it to the number of physical cores using `cmake_host_system_information`. This ensures that if `MPIEXEC_MAX_NUMPROCS` is being used to set up MPI tests with CTest or similar that the tests won't spuriously fail due to OpenMPI refusing to start the application. --- Modules/FindMPI.cmake | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/Modules/FindMPI.cmake b/Modules/FindMPI.cmake index 578fcd2..7f4c44c 100644 --- a/Modules/FindMPI.cmake +++ b/Modules/FindMPI.cmake @@ -1036,13 +1036,8 @@ set(MPIEXEC_NUMPROC_FLAG "-n" CACHE STRING "Flag used by MPI to specify the num set(MPIEXEC_PREFLAGS "" CACHE STRING "These flags will be directly before the executable that is being run by mpiexec.") set(MPIEXEC_POSTFLAGS "" CACHE STRING "These flags will be placed after all flags passed to mpiexec.") -# Set the number of processes to the processor count and the previous default -# of 2 if that couldn't be determined. -include(${CMAKE_CURRENT_LIST_DIR}/ProcessorCount.cmake) -ProcessorCount(_MPIEXEC_NUMPROCS) -if("${_MPIEXEC_NUMPROCS}" EQUAL "0") - set(_MPIEXEC_NUMPROCS 2) -endif() +# Set the number of processes to the physical processor count +cmake_host_system_information(RESULT _MPIEXEC_NUMPROCS QUERY NUMBER_OF_PHYSICAL_CORES) set(MPIEXEC_MAX_NUMPROCS "${_MPIEXEC_NUMPROCS}" CACHE STRING "Maximum number of processors available to run MPI applications.") unset(_MPIEXEC_NUMPROCS) mark_as_advanced(MPIEXEC_EXECUTABLE MPIEXEC_NUMPROC_FLAG MPIEXEC_PREFLAGS MPIEXEC_POSTFLAGS MPIEXEC_MAX_NUMPROCS) -- cgit v0.12