From: "lihuisong (C)" <lihuisong@huawei.com>
To: Ferruh Yigit <ferruh.yigit@amd.com>, <dev@dpdk.org>
Cc: <thomas@monjalon.net>, <andrew.rybchenko@oktetlabs.ru>,
<liuyonglong@huawei.com>, Gagandeep Singh <g.singh@nxp.com>,
Hemant Agrawal <hemant.agrawal@nxp.com>,
Simei Su <simei.su@intel.com>, Qi Zhang <qi.z.zhang@intel.com>,
Qiming Yang <qiming.yang@intel.com>,
Junfeng Guo <junfeng.guo@intel.com>
Subject: Re: [PATCH v3 0/2] ethdev: add the check for PTP capability
Date: Thu, 11 Jan 2024 14:25:58 +0800 [thread overview]
Message-ID: <7ecc6f3b-78f8-6421-307d-2c6c484c6109@huawei.com> (raw)
In-Reply-To: <665b0b6e-1ad9-a692-39cb-9e45e6b78b08@huawei.com>
Hi Ferruh,
在 2023/11/23 19:56, lihuisong (C) 写道:
>
> 在 2023/11/2 7:39, Ferruh Yigit 写道:
>> timesync_read_rx_timestamp
>> On 9/21/2023 12:59 PM, lihuisong (C) wrote:
>>> add ice & igc maintainers
>>>
>>> 在 2023/9/21 19:06, Ferruh Yigit 写道:
>>>> 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"?
>>>>
>>> It indicates whether the device supports PTP or enable PTP feature.
>>>
>> We have 'rte_eth_timesync_enable()' and 'rte_eth_timesync_disable()'
>> APIs to control PTP support.
> No, this is just to control it.
> we still need to like a device capablity to report application if the
> port support to call this API, right?
>>
>> But when mention from "offload", it is something device itself does.
>>
>> PTP is a protocol (IEEE 1588), and used to synchronize clocks.
>> What I get is protocol can be parsed by networking stack and it can be
>> used by application to synchronize clock.
>>
>> When you are refer to "PTP offload", does it mean device (NIC)
>> understands the protocol and parse it to synchronize device clock with
>> other devices?
> Good point. PTP offload is unreasonable.
> But the capablity is required indeed.
> What do you think of introducing a RTE_ETH_DEV_PTP in
> dev->data->dev_flags for PTP feature?
Can you take a look at this discussion line again?
Let's introduce a RTE_ETH_DEV_PTP in dev->data->dev_flags to reveal if
the device support PTP feature.
>>
>>
>> We have 'rte_eth_timesync_*()' APIs, my understanding is application
>> parses the PTP protocol, and it may use this information to configure
>> NIC to synchronize its clock, but it may also use PTP provided
>> information to sync any other clock. Is this understanding correct?
>>
>>
>>> If TIMESTAMP offload is not for PTP, I don't know what the point of
>>> this
>>> offload independent existence is.
>>>
>> TIMESTAMP offload request device to add timestamp to mbuf in ingress,
>> and use mbuf timestamp to schedule packet for egress.
> Agree.
>>
>> Technically this time-stamping can be done by driver, but if offload
>> set, HW timestamp is used for it.
>>
>> Rx timestamp can be used for various reasons, like debugging and
>> performance/latency analyses, etc..
>>
>>
>>>>>> 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.
>>> understand.
>>>>>>> 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.
>>>>> 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?
>>> *-->igc code:*
>>>
>>> Having following codes in igc_recv_scattered_pkts():
>>>
>>> if (rxq->offloads & RTE_ETH_RX_OFFLOAD_TIMESTAMP) {
>>> uint32_t *ts = rte_pktmbuf_mtod_offset(first_seg,
>>> uint32_t *, -IGC_TS_HDR_LEN);
>>> rxq->rx_timestamp = (uint64_t)ts[3] * NSEC_PER_SEC +
>>> ts[2];
>>> rxm->timesync = rxq->queue_id;
>>> }
>>> Note：this rxm->timesync will be used in timesync_read_rx_timestamp()
>>>
>> Above code requires TIMESTAMP offload to set timesync, but this
>> shouldn't be a requirement. Usage seems mixed.
>>
>>> *-->ice code:*
>>>
>>> #ifndef RTE_LIBRTE_ICE_16BYTE_RX_DESC
>>> if (ice_timestamp_dynflag > 0 &&
>>> (rxq->offloads & RTE_ETH_RX_OFFLOAD_TIMESTAMP)) {
>>> rxq->time_high =
>>> rte_le_to_cpu_32(rxd.wb.flex_ts.ts_high);
>>> if (unlikely(is_tsinit)) {
>>> ts_ns = ice_tstamp_convert_32b_64b(hw, ad, 1,
>>> rxq->time_high);
>>> rxq->hw_time_low = (uint32_t)ts_ns;
>>> rxq->hw_time_high = (uint32_t)(ts_ns >> 32);
>>> is_tsinit = false;
>>> } else {
>>> if (rxq->time_high < rxq->hw_time_low)
>>> rxq->hw_time_high += 1;
>>> ts_ns = (uint64_t)rxq->hw_time_high << 32 |
>>> rxq->time_high;
>>> rxq->hw_time_low = rxq->time_high;
>>> }
>>> rxq->hw_time_update = rte_get_timer_cycles() /
>>> (rte_get_timer_hz() / 1000);
>>> *RTE_MBUF_DYNFIELD(rxm,
>>> (ice_timestamp_dynfield_offset),
>>> rte_mbuf_timestamp_t *) = ts_ns;
>>> pkt_flags |= ice_timestamp_dynflag;
>>> }
>>>
>>> if (ad->ptp_ena && ((rxm->packet_type & RTE_PTYPE_L2_MASK) ==
>>> RTE_PTYPE_L2_ETHER_TIMESYNC)) {
>>> rxq->time_high =
>>> rte_le_to_cpu_32(rxd.wb.flex_ts.ts_high);
>>> rxm->timesync = rxq->queue_id;
>>> pkt_flags |= RTE_MBUF_F_RX_IEEE1588_PTP;
>>> }
>>> #endif
>>>
>>> Note: rxm->timesync and rxq->time_high will be used in
>>> timesync_read_rx_timestamp()
>>>
>> This usage looks good, if TIMESTAMP offload enabled mbuf dynamic field
>> and flag set accordingly.
> hns3 also implemented PTP as ice did.
>>
>> And if PTP enabled, and PTP packet type detected relevant flag set in
>> mbuf, and timesyc value set to use later for
>> 'timesync_read_rx_timestamp()'.
> Yes.
>>
>>
>> Although above usage looks correct, I can see in 'ice_timesync_enable()'
>> TIMESTAMP offload is used requirement to enable timesync.
>> TIMESTAMP offload seems used as way to enable HW timestamp, as Hemant
>> mentioned what is done is dpaa2.
>>
>>
>>>>
>>>>>> 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:[~2024-01-11 6:26 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)
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) [this message]
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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