Note - to vote for this idea, please go here: http://community.tableau.com/ideas/1108
Please include this feature in next version of Tableau.
Under "Background Tasks", against each running tasks/jobs there should be an option to kill the task if not fancy 'pause/resume' is provided.
Having to restart the server, for killing background tasks, is really painful and neither good for Tableau users nor gives a good outlook.
Also, please add "Server" as an available Topic, while posting ideas.