Sometimes the queue would have open machines and jobs waiting, but wouldn’t start the jobs. The comment on these jobs would be that they weren’t running, they were waiting for starving jobs to finish. The default setting is to not run any jobs when there are jobs that have been waiting for at least 24 hours (classified as starving). This behavior was disabled by editing /var/spool/pbs/sched_priv/sched_config and change the help_starving_jobs option to false.