jenkins: request 16 HT cores and run ctest -j8

The new Jenkins system lets runPod request cores via cpus: (HT cores; default
4 = the old 2-physical-core pod). Request cpus:16 = 8 physical cores and run
ctest -j8: 2 concurrent 4-rank tests = 8 ranks, one per physical core, no HT
oversubscription. Should roughly halve test wall-time (~800s -> ~400s).

Author: the-hampel

jenkins/Jenkinsfile

@@ -98,13 +98,11 @@ def runBuild = { String platform, String prefix, List<String> envs ->
         try {
           /* Tests run 4 MPI ranks each (PROCESSORS property) with binding
              disabled (see envs), so ctest -j is a core budget. The Linux build
-             pod's cpuset (3-4,99-100) is only 2 physical cores + their HT
-             siblings, so -j2 matches the 2 real cores: integration tests
-             (PROCESSORS=4 > 2) run one at a time across all 4 logical CPUs,
-             and unit tests pack 2-up without oversubscribing. Total wall-time
-             is bounded by the 2 physical cores regardless. macOS m1 nodes have
-             ~10 cores, so -j8 = 2 concurrent 4-rank tests. */
-          def ctestJobs = macos ? 8 : 2
+             pod requests cpus:16 (HT cores) = 8 physical cores, so -j8 runs 2
+             concurrent 4-rank tests = 8 ranks, one per physical core, with no
+             HT oversubscription. macOS m1 nodes have ~10 cores, so -j8 = 2
+             concurrent 4-rank tests too. */
+          def ctestJobs = 8
           sh "ctest --output-on-failure -j${ctestJobs}"
         } catch (exc) {
           archiveArtifacts(artifacts: 'Testing/Temporary/LastTest.log')
@@ -139,8 +137,10 @@ for (int i = 0; i < dockerPlatforms.size(); i++) {
   platforms[platform] = { ->
     stage(platform) {
       timeout(time: 2, unit: 'HOURS') {
+        /* cpus: 16 HT cores = 8 physical; tests run at ctest -j8 (see runBuild). */
         runPod(tag: platform,
           devShm: true,
+          cpus: 16,
           mounts: mounts) {
           runBuild(platform, installBase, [])
         }