On Mon, 28 Dec 2020 11:22:32 -0500 Willem de Bruijn wrote: > From: Willem de Bruijn <will...@google.com> > > Add optional PTP hardware timestamp offload for virtio-net. > > Accurate RTT measurement requires timestamps close to the wire. > Introduce virtio feature VIRTIO_NET_F_RX_TSTAMP. If negotiated, the > virtio-net header is expanded with room for a timestamp. A host may > pass receive timestamps for all or some packets. A timestamp is valid > if non-zero. > > The timestamp straddles (virtual) hardware domains. Like PTP, use > international atomic time (CLOCK_TAI) as global clock base. It is > guest responsibility to sync with host, e.g., through kvm-clock.
Would this not be confusing to some user space SW to have a NIC with no PHC deliver HW stamps? I'd CC Richard on this, unless you already discussed with him offline.
