HI Ferruh,
> On 9/21/2023 11:02 AM, lihuisong (C) wrote:
> > Hi Ferruh,
> >
> > Sorry for my delay reply because of taking a look at all PMDs
> > implementation.
> >
> >
> > 在 2023/9/16 1:46, Ferruh Yigit 写道:
> >> On 8/17/2023 9:42 AM, Huisong Li wrote:
> >>> From the first version of ptpclient, it seems that this example
> >>> assume that the PMDs support the PTP feature and enable PTP by
> >>> default. Please see commit ab129e9065a5 ("examples/ptpclient: add
> >>> minimal PTP client") which are introduced in 2015.
> >>>
> >>> And two years later, Rx HW timestamp offload was introduced to
> >>> enable or disable PTP feature in HW via rte_eth_rxmode. Please see
> >>> commit 42ffc45aa340 ("ethdev: add Rx HW timestamp capability").
> >>>
> >> Hi Huisong,
> >>
> >> As far as I know this offload is not for PTP.
> >> PTP and TIMESTAMP are different.
> > If TIMESTAMP offload cannot stand for PTP, we may need to add one new
> > offlaod for PTP.
> >
>
> Can you please detail what is "PTP offload"?
>
> >>
> >> PTP is a protocol for time sync.
> >> Rx TIMESTAMP offload is to ask HW to add timestamp to mbuf.
> > Yes.
> > But a lot of PMDs actually depand on HW to report Rx timestamp
> > releated information because of reading Rx timestamp of PTP SYNC
> > packet in read_rx_timestamp API.
> >
>
> HW support may be required for PTP but this doesn't mean timestamp
> offload is used.
>
> >>
> >>> And then about four years later, ptpclient enable Rx timestamp
> >>> offload because some PMDs require this offload to enable. Please see
> >>> commit 7a04a4f67dca ("examples/ptpclient: enable Rx timestamp
> offload").
> >>>
> >> dpaa2 seems using TIMESTAMP offload and PTP together, hence they
> >> updated ptpclient sample to set TIMESTAMP offload.
[Hemant] In case of dpaa2, we need to enable HW timestamp for PTP. In the
current dpaa2 driver
If the code is compiled with, RTE_LIBRTE_IEEE1588, we are enabling the HW
timestamp
Otherwise, we are only enabling it when the TIMESTAMP offload is selected.
We added patch in ptpclient earlier to pass the timestamp offload, however
later we also updated the driver to do it by default.
> > There are many PMDs doing like this, such as ice, igc, cnxk, dpaa2,
> > hns3 and so on.
> >
>
> Can you please point the ice & igc code, cc'ing their maintainers, we can look
> together?
>
>
> >>
> >> We need to clarify dpaa2 usage.
> >>
> >>> By all the records, this is more like a process of perfecting PTP
> >>> feature.
> >>> Not all network adaptors support PTP feature. So adding the check
> >>> for PTP capability in ethdev layer is necessary.
> >>>
> >> Nope, as PTP (IEEE1588/802.1AS) implemented as dev_ops, and ops
> >> already checked, so no additional check is needed.
> > But only having dev_ops about PTP doesn't satisfy the use of this feature.
> > For example,
> > there are serveal network ports belonged to a driver on one OS, and
> > only one port support PTP function.
> > So driver needs one *PTP* offload.
> >>
> >> We just need to clarify TIMESTAMP offload and PTP usage and find out
> >> what is causing confusion.
> > Yes it is a little bit confusion.
> > There are two kinds of implementation:
> > A： ixgbe and txgbe (it seems that their HW is similar) don't need
> > TIMESTAMP offload，and only use dev_ops to finish PTP feature.
> > B: saving "Rx timestamp related information" from Rx description when
> > receive PTP SYNC packet and
> > report it in read_rx_timestamp API.
> > For case B, most of driver use TIMESTAMP offload to decide if driver
> > save "Rx timestamp related information.
> > What do you think about this, Ferruh?
> >> I would be great if you can help on clarification, and update
> >> documentation or API comments, or what ever required, for this.
> > ok
> >>
> >>> ---
> >>> v3:
> >>> - patch [2/3] for hns3 has been applied and so remove it.
> >>> - ops pointer check is closer to usage.
> >>>
> >>> Huisong Li (2):
> >>> examples/ptpclient: add the check for PTP capability
> >>> ethdev: add the check for the valitity of timestamp offload
> >>>
> >>> examples/ptpclient/ptpclient.c | 5 +++
> >>> lib/ethdev/rte_ethdev.c | 57
> >>> +++++++++++++++++++++++++++++++++-
> >>> 2 files changed, 61 insertions(+), 1 deletion(-)
> >>>
> >> .
