decrease iterations when only 1 core is available
decrease iterations when only 1 core is available

NicolasSchnitzler/dtk,NicolasSchnitzler/dtk,d-tk/dtk,NicolasSchnitzler/dtk,NicolasSchnitzler/dtk,d-tk/dtk,d-tk/dtk,d-tk/dtk,d-tk/dtk,d-tk/dtk