If in case you have Tableau Admin access, just navigate to Admin tab> maintenance and you will have varies options like Site activity, user activity, View performance history and so on which should provide the required details of the usage and performance.
In case you don't have admin access, another simple way to check this out is by navigating the individual dashboard and click on "Who has seen this view" link at the bottom of the Dashboard and get the statistics of the usage alone.
Other option is to create a Dashboard with required information connecting to Tableau PostreSQL.
You can check default report in maintenance in admin tab for Tableau 8.2.
If you are using Tableau 9, You can navigate to below mentioned page
Connect to Tableau server database and create your own view according to your need.
More details Connecting to the Tableau Server Database
Let me know if this has help you
Atul Vitthal Yadav