Does DPDK provide RX timestamps?

Does DPDK provide RX timestamps?

[Dpdk Newbie]

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Hi. I am using Intel (i210) and AWS ENA network interface cards.

I would like to measure the following RX latencies:

1) NIC to DPDK packet ring buffer
2) DPDK packet ring buffer to application via rte_eth_rx_burst.

I don't mind measuring in nanoseconds or CPU cycles.

Unfortunately I cannot find any mention of hardware timestamps.

I found brief references to mbuf containing a timestamp in the dynamic
fields, but nothing definitive.

Could someone please clarify what the situation is?

Thanks,

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Re: Does DPDK provide RX timestamps?

[Stephen Hemminger]

On Sun, 8 Sep 2024 23:31:36 +0100
Dpdk Newbie <dpdkuser77@gmail.com> wrote:

> Hi. I am using Intel (i210) and AWS ENA network interface cards.
> 
> I would like to measure the following RX latencies:
> 
> 1) NIC to DPDK packet ring buffer
> 2) DPDK packet ring buffer to application via rte_eth_rx_burst.
> 
> I don't mind measuring in nanoseconds or CPU cycles.
> 
> Unfortunately I cannot find any mention of hardware timestamps.
> 
> I found brief references to mbuf containing a timestamp in the dynamic
> fields, but nothing definitive.
> 
> Could someone please clarify what the situation is?
> 
> Thanks,

Depends on the hardware, and the dynamic field for rx timestamp
also varies in its clock value.  Some are ticks, some are us, some are ns;
and the base is arbitrary so difficult to use for packet capture.

Re: Does DPDK provide RX timestamps?

[fengchengwen]

On 2024/9/9 8:13, Stephen Hemminger wrote:
> On Sun, 8 Sep 2024 23:31:36 +0100
> Dpdk Newbie <dpdkuser77@gmail.com> wrote:
> 
>> Hi. I am using Intel (i210) and AWS ENA network interface cards.
>>
>> I would like to measure the following RX latencies:
>>
>> 1) NIC to DPDK packet ring buffer
>> 2) DPDK packet ring buffer to application via rte_eth_rx_burst.

Some packet generator support delay measurement, could construct two tests:
1. run with enabled hairpin
   some NIC support hairpin (the data write to memory and resend by hardware again)
   if the NIC don't support hairpin, could use mac outer loop.
2. run with normal mode

According compare the two delay.

>>
>> I don't mind measuring in nanoseconds or CPU cycles.
>>
>> Unfortunately I cannot find any mention of hardware timestamps.
>>
>> I found brief references to mbuf containing a timestamp in the dynamic
>> fields, but nothing definitive.
>>
>> Could someone please clarify what the situation is?
>>
>> Thanks,
> 
> Depends on the hardware, and the dynamic field for rx timestamp

As I know, this Rx timestamp dynamic field is mainly used by PTP(IEEE1588).

> also varies in its clock value.  Some are ticks, some are us, some are ns;
> and the base is arbitrary so difficult to use for packet capture.

Yes

> .
> 

RE: Does DPDK provide RX timestamps?

[Brandes, Shai]

> מאת: Dpdk Newbie <dpdkuser77@gmail.com
> <mailto:dpdkuser77@gmail.com> >
> תאריך: 9 בספט׳ 2024 01:32
> נושא: [EXTERNAL] Does DPDK provide RX timestamps?
> אל: dev@dpdk.org <mailto:dev@dpdk.org>
> ‏עותק:
> 
> 
> 
> Hi. I am using Intel (i210) and AWS ENA network interface cards.
> 
> 
> 
> I would like to measure the following RX latencies:
> 
> 1) NIC to DPDK packet ring buffer
> 
> 2) DPDK packet ring buffer to application via rte_eth_rx_burst.
> 
[Brandes, Shai] Hi, currently AWS doesn’t support HW timestamping.
In order to get the full Rx latency you need to measure rte_eth_rx_burst as it is mapped to ENA driver routine eth_ena_recv_pkts which covers the entire flow including NIC to DPDK packet ring buffer flow (ena_com_rx_pkt)

All the best
Shai

> I don't mind measuring in nanoseconds or CPU cycles.
> 
> 
> Unfortunately I cannot find any mention of hardware timestamps.
> 
> 
> I found brief references to mbuf containing a timestamp in the dynamic
> fields, but nothing definitive.
> 
> Could someone please clarify what the situation is?
> 
> Thanks,

Re: Does DPDK provide RX timestamps?

[Dpdk Newbie]

I was looking at the source code but I'm more OOP C++ than C. I found
eth_ena_recv_pkts but is it possible for me to add a software
timestamp before the mbuf is added to the ring buffer? This would be
incredibly useful.

On Mon, 9 Sept 2024 at 09:31, Brandes, Shai <shaibran@amazon.com> wrote:
>
>
> > מאת: Dpdk Newbie <dpdkuser77@gmail.com
> > <mailto:dpdkuser77@gmail.com> >
> > תאריך: 9 בספט׳ 2024 01:32
> > נושא: [EXTERNAL] Does DPDK provide RX timestamps?
> > אל: dev@dpdk.org <mailto:dev@dpdk.org>
> > ‏עותק:
> >
> >
> >
> > Hi. I am using Intel (i210) and AWS ENA network interface cards.
> >
> >
> >
> > I would like to measure the following RX latencies:
> >
> > 1) NIC to DPDK packet ring buffer
> >
> > 2) DPDK packet ring buffer to application via rte_eth_rx_burst.
> >
> [Brandes, Shai] Hi, currently AWS doesn’t support HW timestamping.
> In order to get the full Rx latency you need to measure rte_eth_rx_burst as it is mapped to ENA driver routine eth_ena_recv_pkts which covers the entire flow including NIC to DPDK packet ring buffer flow (ena_com_rx_pkt)
>
> All the best
> Shai
>
> > I don't mind measuring in nanoseconds or CPU cycles.
> >
> >
> > Unfortunately I cannot find any mention of hardware timestamps.
> >
> >
> > I found brief references to mbuf containing a timestamp in the dynamic
> > fields, but nothing definitive.
> >
> > Could someone please clarify what the situation is?
> >
> > Thanks,
>