In Jenkins there is an option in Manage Jenkins > Configure System which allows users to manually set the number of polling threads to any number.
This option is only available to Jenkins installations with over 10 jobs which all are using polling. After 10 jobs are configured for SCM polling, then this option becomes available.
Sometimes Jenkins will not poll all jobs because there is polling happening in other jobs (or polling is stuck).
If you encounter this issue it is best to increase the total number of polling threads to a higher number.
If polling operations are still stuck then perform a thread dump (
kill -3 $PID or
jstack $PID) and provide CloudBees support with this information.
Polling can be triggered manually by POSTing to
Navigating to this via a browser will provide an option to post to trigger the polling manually.