[dpdk-users] Hardware Timestamping with Intel X710

[Marco Faltelli]

Hi all,
I'm running the l3fwd DPDK sample application and using Moongen's HW NIC
timestamp capabilities through this suite
<https://github.com/ztz1989/software-switches/tree/artifacts> for
benchmarking l3fwd's latency with 64B packets.
I'm running tests both with Intel X520 and X710 NICs.
While X520 NICs give me meaningful values (e.g. 8.5 us at 10Gbps, 7.86 us
at 5Gbps, 10 us at 1Gbps), Intel X710 show an unexpected increase when
running at line rate (16.45 us at 10Gbps), while at lower rates results are
quite similar as Intel X520 (7.42 us at 5Gbps, 8.24 us at 1Gbps). Even
playing with different parameters (such as DPDK's l3fwd minimum batch
transmit size) the problem still occurs.
Do you have any insight about Intel X710 timestamping and how this can
happen?
Thanks,
Marco