@Sanjeev_Kumar I have a similar use case to reuse job cluster across two tasks. Out of two tasks, one task is running for long time when both task runs in parallel, but the same task finish quick when it runs alone. Please note that i have if control to run the task in parallel in jobs. 

What could be the cause of long running one same task when it runs parellel. Can we use Dynamic resource allocation in job cluster for this scenario, please give more details and guidance on this issue.