revamp cmake MPI detection

we honor user requested MPI installations using MPI_PATH first,
and check afterwards for MPICH and Open MPI in the default
Ubuntu and RHEL installation directories.

CMakeLists.txt

@@ -3,29 +3,23 @@
 # ########################################################################
 #Adding pthread flag for linking
 set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pthread")
-macro(check_mpi mpi_compiler mpi_lib_a mpi_lib_so)
-    find_program(MPI_MPICXX ${mpi_compiler})
+macro(check_mpi mpi_compiler mpi_lib_a mpi_lib_so mpi_bin_dir mpi_base_lib_dir mpi_inc_dir)
+    find_program(MPI_MPICXX ${mpi_compiler} PATHS ${mpi_bin_dir} NO_DEFAULT_PATH)
     if (MPI_MPICXX)
         message ("-- ${mpi_compiler} found @ ${MPI_MPICXX}")
-        if (${CMAKE_VERSION} VERSION_LESS "3.20.0")
-            get_filename_component(mpi.tmpdir ${MPI_MPICXX} DIRECTORY)
-            get_filename_component(mpi_base_dir ${mpi.tmpdir} DIRECTORY)
-        else()
-            cmake_path(GET MPI_MPICXX PARENT_PATH mpi.tmpdir)
-            cmake_path(GET mpi.tmpdir PARENT_PATH mpi_base_dir)
-        endif()
-        find_file(MPI_H mpi.h PATHS ${mpi_base_dir} PATH_SUFFIXES include include/x86_64-linux-gnu ${ARGN} {REQUIRED)
-        if (${CMAKE_VERSION} VERSION_LESS "3.20.0")
-            get_filename_component(mpi_inc_dir ${MPI_H} DIRECTORY)
-        else()
-            cmake_path(GET MPI_H PARENT_PATH mpi_inc_dir)
-        endif()
-        message ("-- mpi.h is in ${mpi_inc_dir}")
-        find_file(MPI_LIB NAMES ${mpi_lib_so} ${mpi_lib_a} PATHS ${mpi_base_dir} PATH_SUFFIXES lib lib64 lib/x86_64-linux-gnu REQIRED)
+        find_file(MPI_H mpi.h PATHS ${mpi_inc_dir} NO_DEFAULT_PATH)
+        message ("-- mpi.h is in ${MPI_H}")
+        find_file(MPI_LIB NAMES ${mpi_lib_so} ${mpi_lib_a} PATHS ${mpi_base_lib_dir} PATH_SUFFIXES lib lib64 lib/x86_64-linux-gnu NO_DEFAULT_PATH)
         message ("-- libmpi is ${MPI_LIB}")
-        add_definitions(-DMPI_SUPPORT)
-        include_directories(${mpi_inc_dir})
-        link_libraries(${MPI_LIB})
+	if (NOT MPI_H OR NOT MPI_LIB)
+	    set (MPI_MPICXX "MPI_MPICXX-NOTFOUND")
+	    set (MPI_H "MPI_H-NOTFOUND")
+	    set (MPI_LIB "MPI_LIB-NOTFOUND")
+	else()
+            add_definitions(-DMPI_SUPPORT)
+            include_directories(${mpi_inc_dir})
+            link_libraries(${MPI_LIB})
+	endif()
     else()
         message ("-- ${mpi_compiler} not found")
     endif()
@@ -60,6 +54,7 @@ include(ROCMClients)
 
 # Build variables
 option(NO_MPI "Build RCCL-tests without MPI support.")
+option(MPI_PATH "Use MPI in the specified directory.")
 ## Get default GPU targets using rocm_check_target_ids
 rocm_check_target_ids(
     DEFAULT_AMDGPU_TARGETS
@@ -68,13 +63,35 @@ rocm_check_target_ids(
 set(AMDGPU_TARGETS "${DEFAULT_AMDGPU_TARGETS}" CACHE STRING "List of specific machine types for these tests to target.")
 
 if (NOT NO_MPI)
-    # Check for MPICH first
-    check_mpi(mpicxx.mpich libmpich.a libmpich.so include/x86_64-linux-gnu/mpich)
+    # CHECK for MPI Path first. User requested this directory explicitely
+    if (MPI_PATH)
+        set(mpi_spec_bin_dir "${MPI_PATH}/bin")
+	set(mpi_spec_inc_dir "${MPI_PATH}/include")
+        check_mpi(mpicxx libmpi.a libmpi.so ${mpi_spec_bin_dir} ${MPI_PATH} ${mpi_spec_inc_dir})
+	if (NOT MPI_MPICXX)
+            # Since the user explicitely requested this directory, abort if something went wrong.
+	    MESSAGE(FATAL_ERROR "Could not find MPI in ${MPI_PATH}")
+        endif()
+    endif()
 
-    # Check for MPI in general. If we find mpicxx, we don't know whether its
-    # MPICH or another MPI implementation
+    # Check for MPICH Ubuntu installation
     if (NOT MPI_MPICXX)
-        check_mpi(mpicxx libmpi.a libmpi.so)
+        check_mpi(mpicxx.mpich libmpich.a libmpich.so /usr/bin /usr /usr/include/x86_64-linux-gnu/mpich)
+    endif()
+
+    # Check for Open MPI Ubuntu installation
+    if (NOT MPI_MPICXX)
+        check_mpi(mpicxx.openmpi libmpi.a libmpi.so /usr/bin  /usr/lib/x86_64-linux-gnu/openmpi /usr/lib/x86_64-linux-gnu/openmpi/include)
+    endif()
+
+    # Check for MPICH RHEL installation
+    if (NOT MPI_MPICXX)
+        check_mpi(mpicxx libmpich.a libmpich.so /usr/lib64/mpich/bin /usr/lib64/mpich /usr/include/mpich-x86_64)
+    endif()
+
+    # Check for Open MPI RHEL installation
+    if (NOT MPI_MPICXX)
+        check_mpi(mpicxx libmpi.a libmpi.so /usr/lib64/openmpi/bin /usr/lib64/openmpi /usr/include/openmpi-x64_64)
     endif()
 
     if (NOT MPI_MPICXX)
@@ -91,7 +108,7 @@ add_subdirectory(src)
 
 # Create ROCm standard packages
 rocm_create_package(
-    NAME rccl-separate-tests
+    NAME rccl-tests
     DESCRIPTION "Tests for the ROCm Communication Collectives Library"
     MAINTAINER "RCCL Maintainer <rccl-maintainer@amd.com>"
 )

README.md

@@ -30,8 +30,9 @@ $ make
 When using the cmake build procedure, please make sure that RCCL has also been built using cmake (i.e. not using the install.sh script), since cmake will check
 for cmake target and config files that are created during the RCCL build.
 
-Using the cmake method also has the advantage that the build is automatically checking for MPI installations, i.e. it is not necessary to explicitley request
-MPI builds. A user can explicitely disable MPI builds by adding the -DNO_MPI=1 flag to the cmake command line.
+Using the cmake method also has the advantage that the build is automatically checking for MPI installations, i.e. it is not necessary to explicitly request
+MPI builds. A user can request to use a particular MPI library by using the MPI_PATH variable. MPI support can be explicitely disabled by adding the -DNO_MPI=1
+flag to the cmake command line.
 
 
 ## Usage