Note that some values of ProctrackType are unable to identify all processses.

doc/man/man1/scontrol.1

@@ -107,7 +107,9 @@ Print a listing of the process IDs in a job step (if JOBID.STEPID is provided),
 or all of the job steps in a job (if JOBID is provided), or all of the job
 steps in all of the jobs on the local node (if JOBID is not provided or JOBID
 is "*").  This will work only with processes on node on which scontrol is run,
-and only for those processes spawned by SLURM and their descendants.
+and only for those processes spawned by SLURM and their descendants. Note that 
+some SLURM configurations (\fIProctrackType\fP value of \fIpgid\fP or \fIaix\fP) 
+are unable to identify all processes associated with a job or job step.
 
 Note that the NodeName option is only really useful when you have multiple
 slurmd daemons running on the same host machine.  Multiple slurmd daemons on

src/plugins/proctrack/pgid/proctrack_pgid.c

@@ -186,6 +186,6 @@ slurm_container_wait(uint32_t cont_id)
 extern int
 slurm_container_get_pids(uint32_t cont_id, pid_t **pids, int *npids)
 {
-	error("proctrack/aix does not implement slurm_container_get_pids");
+	error("proctrack/pgid does not implement slurm_container_get_pids");
 	return SLURM_ERROR;
 }