CTest: Add options to control test process affinity to CPUs

In commit v2.8.0~170 (ENH: Added ctest test options PROCESSORS and
RUN_SERIAL, 2009-09-07) CTest learned to track the number of processors
allocated to running tests in order to balance it against the desired
level of parallelism.  Extend this idea by introducing a new
`PROCESSOR_AFFINITY` test property to ask that CTest run a test
with the CPU affinity mask set.  This will allow a set of tests
that are running concurrently to use disjoint CPU resources.

2 files changed, 21 insertions, 0 deletions

diff --git a/Tests/CMakeLib/CMakeLists.txt b/Tests/CMakeLib/CMakeLists.txt
index 06df53f..126076d 100644
--- a/Tests/CMakeLib/CMakeLists.txt
+++ b/Tests/CMakeLib/CMakeLists.txt
@@ -49,3 +49,6 @@ if(TEST_CompileCommandOutput)
 endif()
 
 add_subdirectory(PseudoMemcheck)
+
+add_executable(testAffinity testAffinity.cxx)
+target_link_libraries(testAffinity CMakeLib)
diff --git a/Tests/CMakeLib/testAffinity.cxx b/Tests/CMakeLib/testAffinity.cxx
new file mode 100644
index 0000000..4b82280
--- /dev/null
+++ b/Tests/CMakeLib/testAffinity.cxx
@@ -0,0 +1,18 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#include "cmAffinity.h"
+
+#include <cstddef>
+#include <iostream>
+#include <set>
+
+int main()
+{
+  std::set<size_t> cpus = cmAffinity::GetProcessorsAvailable();
+  if (!cpus.empty()) {
+    std::cout << "CPU affinity mask count is '" << cpus.size() << "'.\n";
+  } else {
+    std::cout << "CPU affinity not supported on this platform.\n";
+  }
+  return 0;
+}