Experience with the implementation of the MPIT interface

My diploma thesis is about implementing the key part of the MPIT interface and evaluate the capabilities and potentials of this Interface. So far I have implemented the API and some configuration and performance variables. For performance tuning, i was looking for configuration and performance variables where the configuration variables affect the performance variables.  Configure variables are for example transmission protocol thresholds. As performance variable, I implemented, among other things, the time witch is spend during MPI_send calls. There a first limitation of the interface appeared: For average values there is no corresponding performance variable class in the proposed standard. The only way is to provide a Timer and a corresponding call counter to calculate the average by yourself. The disadvantage of this solution is, that the interface user has to make sure, that both variables are reseted  simultaneously. Maybe it would be better if you could define performance variables as average value.
Furthermore there is no standardized way to express if a variable (or a part of it) is global or if it corresponds to a specific rank or MPI communicator. This will likely limit the  usefulness of portable monitoring and tuning tools.