Jason Xing wrote: > BPF program calculates a couple of latency deltas between each tx > timestamping callbacks. It can be used in the real world to diagnose > the kernel behaviour in the tx path. > > Check the safety issues by accessing a few bpf calls in > bpf_test_access_bpf_calls() which are implemented in the patch 3 and 4. > > Check if the bpf timestamping can co-exist with socket timestamping. > > There remains a few realistic things[1][2] to highlight: > 1. in general a packet may pass through multiple qdiscs. For instance > with bonding or tunnel virtual devices in the egress path. > 2. packets may be resent, in which case an ACK might precede a repeat > SCHED and SND. > 3. erroneous or malicious peers may also just never send an ACK. > > [1]: https://lore.kernel.org/all/67a389af981b0_14e0832949d@xxxxxxxxxxxxxxxxxxxxxx.notmuch/ > [2]: https://lore.kernel.org/all/c329a0c1-239b-4ca1-91f2-cb30b8dd2f6a@xxxxxxxxx/ > > Signed-off-by: Jason Xing <kerneljasonxing@xxxxxxxxx> Reviewed-by: Willem de Bruijn <willemb@xxxxxxxxxx>
