improve omp for blocks

4 jobs for master in 8 minutes (queued for 1 minute and 32 seconds)
Status Name Job ID Coverage
  Build
passed build_debug #1087

00:02:44

passed build_opt #1088

00:04:01

 
  Test
passed test_debug #1089

00:00:41

passed test_opt #1090

00:00:32