From: "lihuisong (C)" <lihuisong@huawei.com>
To: Ferruh Yigit <ferruh.yigit@amd.com>,
Hemant Agrawal <hemant.agrawal@nxp.com>,
"dev@dpdk.org" <dev@dpdk.org>, Gagandeep Singh <G.Singh@nxp.com>
Cc: "thomas@monjalon.net" <thomas@monjalon.net>,
"andrew.rybchenko@oktetlabs.ru" <andrew.rybchenko@oktetlabs.ru>,
"liuyonglong@huawei.com" <liuyonglong@huawei.com>
Subject: Re: [PATCH v3 0/2] ethdev: add the check for PTP capability
Date: Thu, 23 Nov 2023 19:40:13 +0800 [thread overview]
Message-ID: <4ca421eb-3a0f-d629-801f-1b99a02a1387@huawei.com> (raw)
In-Reply-To: <d74aaaa7-1ccb-4a34-b7a7-6fcb647bea9f@amd.com>
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-thomas@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(-)
>>>>>>>
>>>>>> .
> .
next prev parent reply other threads:[~2023-11-23 11:40 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-28 13:39 [PATCH 0/3] some bugfixes for PTP Dongdong Liu
2022-06-28 13:39 ` [PATCH 1/3] examples/ptpclient: add the check for PTP capability Dongdong Liu
2022-06-28 13:39 ` [PATCH 2/3] net/hns3: fix fail to receive PTP packet Dongdong Liu
2022-06-28 13:39 ` [PATCH 3/3] ethdev: add the check for the valitity of timestamp offload Dongdong Liu
2022-07-02 8:17 ` [PATCH v2 0/3] some bugfixes for PTP Dongdong Liu
2022-07-02 8:17 ` [PATCH v2 1/3] examples/ptpclient: add the check for PTP capability Dongdong Liu
2022-07-02 8:17 ` [PATCH v2 2/3] net/hns3: fix fail to receive PTP packet Dongdong Liu
2022-07-02 8:17 ` [PATCH v2 3/3] ethdev: add the check for the valitity of timestamp offload Dongdong Liu
2022-07-06 14:57 ` Andrew Rybchenko
2022-07-07 2:05 ` lihuisong (C)
2023-08-17 8:42 ` [PATCH v3 0/2] ethdev: add the check for PTP capability Huisong Li
2023-08-17 8:42 ` [PATCH v3 1/2] examples/ptpclient: " Huisong Li
2023-09-15 17:29 ` Ferruh Yigit
2023-09-21 9:18 ` lihuisong (C)
2023-09-21 11:02 ` Ferruh Yigit
2023-09-21 11:22 ` Hemant Agrawal
2023-10-20 4:05 ` lihuisong (C)
2023-09-21 11:36 ` lihuisong (C)
2023-08-17 8:42 ` [PATCH v3 2/2] ethdev: add the check for the valitity of timestamp offload Huisong Li
2023-09-15 17:46 ` [PATCH v3 0/2] ethdev: add the check for PTP capability Ferruh Yigit
2023-09-21 10:02 ` lihuisong (C)
2023-09-21 11:06 ` Ferruh Yigit
2023-09-21 11:17 ` Hemant Agrawal
2023-10-20 3:58 ` lihuisong (C)
2023-11-01 23:39 ` Ferruh Yigit
2023-11-23 11:40 ` lihuisong (C) [this message]
2023-11-01 23:39 ` Ferruh Yigit
2023-09-21 11:59 ` lihuisong (C)
2023-11-01 23:39 ` Ferruh Yigit
2023-11-23 11:56 ` lihuisong (C)
2024-01-11 6:25 ` lihuisong (C)
2024-01-26 16:54 ` Ferruh Yigit
2024-01-27 1:52 ` lihuisong (C)
2024-01-29 11:16 ` Ferruh Yigit
2024-01-29 13:58 ` lihuisong (C)
2024-01-29 15:00 ` Ferruh Yigit
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