yes we know, that permanent qstat calls will slowdown the qmaster.
We have some customer having the same problem. Currently I have no solution for this except reducing the qstat calls.
Which veriosn of OGE are you using?
The problem is that a qstat call without specification of the job id will get the complete job list. It would be more performant to specify the job you want to have information for with qstat -j YOUR_JOB_ID. For getting information about hosts you might also use the qhost call.