TCP Latency

[netsec () mac com]

Does anyone have a tool they can recommend for obtaining usec latency values for TCP traffic across a DUT?

There are tools that provide usec latency for UDP traffic and other tools that focus on TCP traffic, but only provide 
msec latency granularity.

With all the various products providing all-in-one solutions, there must be some interest in understanding the latency 
at usec levels.

Thanks in advance!