#16: Improve OpenMP integration

CMakeLists.txt

@@ -29,18 +29,16 @@ message(STATUS "CMAKE_CXX_STANDARD: ${CMAKE_CXX_STANDARD}")
 
 option(VT_TV_PYTHON_BINDINGS_ENABLED "Build vt-tv with Python bindings" ON)
 option(VT_TV_OPENMP_ENABLED "Build vt-tv with openMP support" ON)
+option(VT_TV_N_THREADS "Number of threads to use" 2)
 
 include(cmake/load_packages.cmake)
 
 if(APPLE)
   add_compile_options(-ffat-lto-objects)
 endif()
 
-if(VT_TV_OPENMP_ENABLED)
-  set(VT_TV_NUM_THREADS "2" CACHE STRING "Number of threads to use")
-  add_definitions(-DVT_TV_NUM_THREADS=${VT_TV_NUM_THREADS})
-  add_definitions(-DVT_TV_OPENMP_ENABLED=${VT_TV_OPENMP_ENABLED})
-endif()
+add_definitions(-DVT_TV_N_THREADS=${VT_TV_N_THREADS})
+add_definitions(-DVT_TV_OPENMP_ENABLED=${VT_TV_OPENMP_ENABLED})
 
 add_custom_target(vt_tv_examples)
 add_custom_target(vt_tv_tests)

bindings/python/tv.cc

@@ -86,8 +86,8 @@ void tvFromJson(const std::vector<std::string>& input_json_per_rank_list, const
 
     assert(input_json_per_rank_list.size() == num_ranks && "Must have the same number of json files as ranks");
 
-    #ifdef VT_TV_NUM_THREADS
-      const int threads = VT_TV_NUM_THREADS;
+    #ifdef VT_TV_N_THREADS
+      const int threads = VT_TV_N_THREADS;
     #else
       const int threads = 2;
     #endif

setup.py

@@ -45,7 +45,7 @@ def build_extension(self, ext):
     cmake_args = ['-DCMAKE_LIBRARY_OUTPUT_DIRECTORY=' + extdir,
                   '-DPYTHON_EXECUTABLE=' + sys.executable,
                   '-DVTK_DIR=' + vtk_dir,
-                  '-DVT_TV_NUM_THREADS=' + str(n_threads)]
+                  '-DVT_TV_N_THREADS=' + str(n_threads)]
 
     if sys.platform == "darwin":
       import platform

src/vt-tv/utility/parse_render.cc

@@ -80,13 +80,14 @@ void ParseRender::parseAndRender(PhaseType phase_id, std::unique_ptr<Info> info)
 
       info = std::make_unique<Info>();
 
-      #ifdef VT_TV_NUM_THREADS
-        const int threads = VT_TV_NUM_THREADS;
+      #ifdef VT_TV_N_THREADS
+        const int threads = VT_TV_N_THREADS;
       #else
         const int threads = 2;
       #endif
       #ifdef VT_TV_OPENMP_ENABLED
         omp_set_num_threads(threads);
+        fmt::print("vt-tv: Using {} threads\n", threads);
         # pragma omp parallel for
       #endif // VT_TV_OPENMP_ENABLED
         for (int64_t rank = 0; rank < n_ranks; rank++) {