Set process binding for GROMACS. It is single core, but if launched w…

…ith mpirun it is currently free to migrate between cores within a numa domain. On Snellius I've seen some strange issues with occassionally very slow performance (10x slower than normal), potentially due to the OS thread schedulling being silly. Process binding leads to better _and_ more reproducible results

eessi/testsuite/tests/apps/gromacs.py

@@ -113,3 +113,11 @@ def set_omp_num_threads(self):
 
         self.env_vars['OMP_NUM_THREADS'] = omp_num_threads
         log(f'env_vars set to {self.env_vars}')
+
+    @run_after('setup')
+    def set_binding_policy(self):
+        """
+        Default process binding may depend on the launcher used. We've seen some variable performance.
+        Better set it explicitely to make sure process migration cannot cause such variations.
+        """
+        hooks.set_compact_process_binding(self)