core: update CPUs detection

- cache value, evaluate once
- better support for MINGW
- anything in 'cv' namespace
- test: dump number of active threads

modules/core/src/parallel.cpp

@@ -140,13 +140,12 @@
 
 using namespace cv;
 
-namespace cv
-{
-    ParallelLoopBody::~ParallelLoopBody() {}
-}
+namespace cv {
+
+ParallelLoopBody::~ParallelLoopBody() {}
+
+namespace {
 
-namespace
-{
 #ifdef CV_PARALLEL_FRAMEWORK
 #ifdef ENABLE_INSTRUMENTATION
     static void SyncNodes(cv::instr::InstrNode *pNode)
@@ -445,7 +444,7 @@ static SchedPtr pplScheduler;
 
 #endif // CV_PARALLEL_FRAMEWORK
 
-} //namespace
+} // namespace anon
 
 /* ================================   parallel_for_  ================================ */
 
@@ -453,7 +452,7 @@ static SchedPtr pplScheduler;
 static void parallel_for_impl(const cv::Range& range, const cv::ParallelLoopBody& body, double nstripes); // forward declaration
 #endif
 
-void cv::parallel_for_(const cv::Range& range, const cv::ParallelLoopBody& body, double nstripes)
+void parallel_for_(const cv::Range& range, const cv::ParallelLoopBody& body, double nstripes)
 {
 #ifdef OPENCV_TRACE
     CV__TRACE_OPENCV_FUNCTION_NAME_("parallel_for", 0);
@@ -573,7 +572,7 @@ static void parallel_for_impl(const cv::Range& range, const cv::ParallelLoopBody
 #endif // CV_PARALLEL_FRAMEWORK
 
 
-int cv::getNumThreads(void)
+int getNumThreads(void)
 {
 #ifdef CV_PARALLEL_FRAMEWORK
 
@@ -634,7 +633,6 @@ int cv::getNumThreads(void)
 #endif
 }
 
-namespace cv {
 unsigned defaultNumberOfThreads()
 {
 #ifdef __ANDROID__
@@ -656,9 +654,8 @@ unsigned defaultNumberOfThreads()
     }
     return result;
 }
-}
 
-void cv::setNumThreads( int threads_ )
+void setNumThreads( int threads_ )
 {
     CV_UNUSED(threads_);
 #ifdef CV_PARALLEL_FRAMEWORK
@@ -719,7 +716,7 @@ void cv::setNumThreads( int threads_ )
 }
 
 
-int cv::getThreadNum(void)
+int getThreadNum()
 {
 #if defined HAVE_TBB
     #if TBB_INTERFACE_VERSION >= 9100
@@ -841,14 +838,17 @@ T minNonZero(const T& val_1, const T& val_2)
     return (val_1 != 0) ? val_1 : val_2;
 }
 
-int cv::getNumberOfCPUs(void)
+static
+int getNumberOfCPUs_()
 {
     /*
      * Logic here is to try different methods of getting CPU counts and return
      * the minimum most value as it has high probablity of being right and safe.
      * Return 1 if we get 0 or not found on all methods.
     */
-#if defined CV_CXX11
+#if defined CV_CXX11 \
+    && !defined(__MINGW32__) /* not implemented (2020-03) */ \
+
     /*
      * Check for this standard C++11 way, we do not return directly because
      * running in a docker or K8s environment will mean this is the host
@@ -862,13 +862,13 @@ int cv::getNumberOfCPUs(void)
 
 #if defined _WIN32
 
-    SYSTEM_INFO sysinfo;
+    SYSTEM_INFO sysinfo = {};
 #if (defined(_M_ARM) || defined(_M_ARM64) || defined(_M_X64) || defined(WINRT)) && _WIN32_WINNT >= 0x501
     GetNativeSystemInfo( &sysinfo );
 #else
     GetSystemInfo( &sysinfo );
 #endif
-    unsigned ncpus_sysinfo = sysinfo.dwNumberOfProcessors < 0 ? 1 : sysinfo.dwNumberOfProcessors; /* Just a fail safe */
+    unsigned ncpus_sysinfo = sysinfo.dwNumberOfProcessors;
     ncpus = minNonZero(ncpus, ncpus_sysinfo);
 
 #elif defined __APPLE__
@@ -911,6 +911,7 @@ int cv::getNumberOfCPUs(void)
 #endif
 
 #if defined _GNU_SOURCE \
+    && !defined(__MINGW32__) /* not implemented (2020-03) */ \
     && !defined(__EMSCRIPTEN__) \
     && !defined(__ANDROID__)  // TODO: add check for modern Android NDK
 
@@ -933,7 +934,13 @@ int cv::getNumberOfCPUs(void)
     return ncpus != 0 ? ncpus : 1;
 }
 
-const char* cv::currentParallelFramework() {
+int getNumberOfCPUs()
+{
+    static int nCPUs = getNumberOfCPUs_();
+    return nCPUs;  // cached value
+}
+
+const char* currentParallelFramework() {
 #ifdef CV_PARALLEL_FRAMEWORK
     return CV_PARALLEL_FRAMEWORK;
 #else
@@ -941,6 +948,8 @@ const char* cv::currentParallelFramework() {
 #endif
 }
 
+}  // namespace cv::
+
 CV_IMPL void cvSetNumThreads(int nt)
 {
     cv::setNumThreads(nt);

modules/ts/src/ts.cpp

@@ -1099,14 +1099,6 @@ inline static void recordPropertyVerbose(const std::string & property,
     }
 }
 
-inline static void recordPropertyVerbose(const std::string& property, const std::string& msg,
-                                         const char* value, const char* build_value = NULL)
-{
-    return recordPropertyVerbose(property, msg,
-        value ? std::string(value) : std::string(),
-        build_value ? std::string(build_value) : std::string());
-}
-
 #ifdef _DEBUG
 #define CV_TEST_BUILD_CONFIG "Debug"
 #else
@@ -1120,7 +1112,14 @@ void SystemInfoCollector::OnTestProgramStart(const testing::UnitTest&)
     recordPropertyVerbose("cv_vcs_version", "OpenCV VCS version", getSnippetFromConfig("Version control:", "\n"));
     recordPropertyVerbose("cv_build_type", "Build type", getSnippetFromConfig("Configuration:", "\n"), CV_TEST_BUILD_CONFIG);
     recordPropertyVerbose("cv_compiler", "Compiler", getSnippetFromConfig("C++ Compiler:", "\n"));
-    recordPropertyVerbose("cv_parallel_framework", "Parallel framework", cv::currentParallelFramework());
+    const char* parallelFramework = cv::currentParallelFramework();
+    if (parallelFramework)
+    {
+        ::testing::Test::RecordProperty("cv_parallel_framework", parallelFramework);
+        int threads = testThreads > 0 ? testThreads : cv::getNumThreads();
+        ::testing::Test::RecordProperty("cv_parallel_threads", threads);
+        std::cout << "Parallel framework: " << parallelFramework << " (nthreads=" << threads << ")" << std::endl;
+    }
     recordPropertyVerbose("cv_cpu_features", "CPU features", cv::getCPUFeaturesLine());
 #ifdef HAVE_IPP
     recordPropertyVerbose("cv_ipp_version", "Intel(R) IPP version", cv::ipp::useIPP() ? cv::ipp::getIppVersion() :  "disabled");