io stats for NFS calls from a specific NFS export

I am trying to get a profile of NFS stats of from the NFS call hits the isilon to leaving the isilon.

A packet capture provides me with the overall time of the operation, but does not tell me what the breakdown of time is within the operation.

I am seeing a latency issue. I know its not the network ( from the packet capture ), but I need to be able to drill down to how the NFS procedure is completed in terms of time spent in say permission lookup or actual IO.