The workload monitor usually reads the workload data from the workload collector database, which is supplied with data from the statistics files for the individual instances once an hour. This means that you usually cannot show any data that is less than an hour old and has not yet been written to the database.
So that you can also monitor the latest changes in the system performance, there is an additional function, Last Minutes' Load. You can use this function to directly access the statistics files for the individual instances and to display the system performance for any period (such as for the last 15 minutes).
After you have selected an instance, the usual analysis views are available with data for the selected period.
Workload Monitor start page