Improve speed on worker, changed to subprocess.run call for ranks>0

wkmgr.py

@@ -251,22 +251,23 @@ while True:
 
             bashCommand = workstr + " > " + outputdir + str(jobid) + "/std_out.txt 2> " + outputdir + str(jobid) + "/err_out.txt"
             try:
-                p = subprocess.Popen(bashCommand, shell=True)
-                logger.info('Worker startet job.')
+                if rank == 0:
+                    p = subprocess.Popen(bashCommand, shell=True) # start job in background
+                    logger.info('Worker startet job.')
+                else:
+                    completed = subprocess.run(bashCommand, shell=True) # start job and wait for return
+                    logger.info('Job ended, return code: '+str(completed.returncode) )
             except subprocess.CalledProcessError as err:
                 logger.info('Worker ' + str(rank) + ' ERROR:', err)
 
-            WorkerFSM = 3
+            WorkerFSM = (3 if rank == 0 else 0)
 
-    if WorkerFSM == 3: #State 3: Running
+    if WorkerFSM == 3: #State 3: Running, used only for rank = 0 with subprocess.Popen
         if p.poll() is not None:
-            logger.info("Job ended, ret code: " + str(p.returncode))
+            logger.info("Job ended, return code: " + str(p.returncode))
             WorkerFSM = 0
 
-    if rank == 0:
-      time.sleep(0.01)  # to take some load off the node
-    else:
-      time.sleep(1)
+    time.sleep(0.01)  # to take some load off the node
 
 
 logger.info("Worker ended.")