在 2023/11/2 7:39, Ferruh Yigit 写道:
On 10/20/2023 4:58 AM, lihuisong (C) wrote:
在 2023/9/21 19:17, Hemant Agrawal 写道:
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.
It is a little mess for PTP and RTE_LIBRTE_IEEE1588 to use.
Actually, whether PTP code is compiled should not depended on this macro
RTE_LIBRTE_IEEE1588.
There is already a patch by Thomas to remove RTE_LIBRTE_IEEE1588 [1],
agree that this functionality needs some attention.
Removing RTE_LIBRTE_IEEE1588 impact drivers, that is what holding us back.
+1 remove the compile macro RTE_LIBRTE_IEEE1588.
And hns3 had beed removed it.
[1]
https://patchwork.dpdk.org/project/dpdk/patch/20230203132810.14187-1-tho...@monjalon.net/
If there is a capability, it will be perfect, no matter whether it is
TIMESTAMP offload.
What do you think, Ferruh?
Difficulty is to know when to enable HW timestamp, and for some drivers
this may change the descriptor format (to include timestamp), so driver
should set correct datapath functions for this case.
Yes, to get Rx timestamp of PTP packet from descriptor for many NIC.
We know when a HW timer is required, it is required for PTP protocol and
required for TIMESTAMP offload.
TIMESTAMP offload may be unnecessary for some NIC which don't get Rx
timestamp from descriptor(But, IMO, like this hardware is very rare.).
What do you think to dynamically enable it for PTP when
'rte_eth_timesync_enable()' API called, and for TIMESTAMP offload when
the offload is enabled.
Agree above.
At least, this can make sure all NIC can enable PTP feature.
If this works, now new configuration item or offload is required, what
do you think?
The new capability item is required to know if the port support PTP feature.
so application can enable/disable PTP based on this capability.
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(-)
.
.
