After looking at the runtime holistically but not so accurate in the last WPS today it is a bot more restricted, but very accurate way of looking at runtime on the server.
The transaction is STAD:
This is your welcome screen
Note that by default it shows the last 10minutes. You should then select your username (or the username of the person performing the relevant activity) and a restriction to *scmtms/* for either program or transaction.
Then you see something like this:
The interesting piece is the response time and how it is distributed between db and cpu. Memory might also be interesting. Every call to the server is shown here, so one user activity might end up in multiple entries here. Then of course the sum is relevant.
The beauty of this is that it is always there and it is not spoiled by a performance measurement as such. So you can use it to e.g. compare the server time before and after a performance improvement activity and get reliable figures easy.
Of course if the times you see are too high you need other tools to dive a bit deeper, but this is something for the next WPS 😉