[dpdk-users] TimeStamping Packets Generated and Received via Pktgen Application

Paul Emmerich emmericp at net.in.tum.de
Mon Oct 17 00:55:51 CEST 2016


Hi,


Ajinkya D Kadam:
> If yes I would like to modify the pktgen code so that each transmitting and
> received packet is timestamped.  Right now I am exploring the example
> applications  like rxtx_callbacks which timestamps packets in DPDK, Is this
> the right direction to go ?

Check out my packet generator MoonGen
https://github.com/emmericp/MoonGen

It uses the hardware timestamping features (PTP) to do latency 
measurements in the nanosecond-range.

However, if you will run into hardware limitations if you want to 
timestamp *all* packets. This is sometimes supported on RX (e.g., i310, 
X550) but I don't know a NIC that supports this on TX.

As for the precision that is achievable: ~10ns (depending on the NIC) 
with hardware support. Software timestamping will typically result in a 
standard deviation of 200-300ns under load and there will be huge outliers.


  Paul


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