Irule or method to limit concurrent users towards loged in content based on responsetime?

Hi,

We need to protect ceretain applications based on responsetime.

Is there a way to messure the response time on a rest service done during login and based on that, if the response time is above a set threshold, redirect subsequent users to an information page leting them now to come back later.

When response time are under the threshold again, the irule should redirect to the login service again.

I see no problem in writing an iRule to redirect the service dependent on response time, but I can't see how I will ever be able to meassure response time on loged in content (without actually loging in) that can set a variable for the orignial iRule to realise it should start to allow logins again. Becaus by then I will send all users to the information page and by that will not be able to catch the current response time.

Or is it better to count the concurrent number of loged in users at the point when the response time threshold is reached and then allowe logins again when that counter is lowered?

Or are there better ways to solve this?

Best regards

Per Ekman