Re: Issue with DPDK-Burst Replay – No Frame Transmission Observed Despite Successful Replay

[Ivan Malov <ivan.malov@arknetworks.am>]

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Hi,

(please see below)

On Fri, 18 Jul 2025, Gokul K R (MS/ETA7-ETAS) wrote:

> 
> Hi Team,
> 
> I’m currently working with the dpdk-burst-replay tool and encountered an issue during execution. Below are the details:
> 
> 
> __________________________________________________________________________________________________________________________________________________________________________________________
> 
> 
> Observation:
> During replay, we received the following informational message:
> 
> port 0 is not on the good numa id (-1)

Which API was used to check this? Was API [1] used? If not, what does it show
in the absence of 'numactl' command?

[1] https://doc.dpdk.org/api-25.03/rte__ethdev_8h.html#ad032e25f712e6ffeb0c19eab1ec1fd2e

> 
> As per the DPDK mailing list discussions, this warning is typically benign—often seen on NICs like Intel I225/I210, which do not report NUMA affinity. Hence, we proceeded with execution.
> 
> 
> __________________________________________________________________________________________________________________________________________________________________________________________
> 
> 
> Command Used:
> 
> sudo numactl --cpunodebind=0 --membind=0 ./src/dpdk-replay Original_MAC.pcap 0000:01:00.1
> 
> Execution Output:
> 
> preloading Original_MAC.pcap file (of size: 143959 bytes)
> 
> file read at 100.00%
> 
> read 675 pkts (for a total of 143959 bytes). max packet length = 1518 bytes.
> 
> -> Needed MBUF size: 1648
> 
> -> Needed number of MBUFs: 675
> 
> -> Needed Memory = 1.061 MB
> 
> -> Needed Hugepages of 1 GB = 1
> 
> -> Needed CPUs: 1
> 
> -> Create mempool of 675 mbufs of 1648 octets.
> 
> -> Will cache 675 pkts on 1 caches.

What does this 'cache' stand for? Does it refer to the mempool per-lcore cache?
If so, please note that, according to API [2] documentation, cache size "must be
lower or equal to RTE_MEMPOOL_CACHE_MAX_SIZE and n / 1.5", where 'n' stands for
the number of mbufs. Also, documentation says it is advised to choose cache_size
to have "n modulo cache_size == 0". Does your code meet these requirements?

By the looks of it, it doesn't (cache_size = n = 675). Consider to double-check.

[2] https://doc.dpdk.org/api-25.03/rte__mempool_8h.html#a0b64d611bc140a4d2a0c94911580efd5

> 
> 
> __________________________________________________________________________________________________________________________________________________________________________________________
> 
> 
> Issue:
> Despite successful parsing of the pcap file and proper initialization, no frames were transmitted or received on either the sender or receiver sides.

Is this observation based solely on watching APIs [3] and [4] return 0 all the
time? If yes, one can consider to introduce invocations of APIs [5], [6] and [7]
in order to periodically poll and print statistics (may be with 1-second delay),
which may, for example, shed light on mbuf allocation errors (extended stats).

Do statistics display any interesting figures to be discussed?

[3] https://doc.dpdk.org/api-25.03/rte__ethdev_8h.html#a3e7d76a451b46348686ea97d6367f102
[4] https://doc.dpdk.org/api-25.03/rte__ethdev_8h.html#a83e56cabbd31637efd648e3fc010392b

[5] https://doc.dpdk.org/api-25.03/rte__ethdev_8h.html#adec226574c53ae413252c9b15f6f4bab
[6] https://doc.dpdk.org/api-25.03/rte__ethdev_8h.html#a418ad970673eb171673185e36044fd79
[7] https://doc.dpdk.org/api-25.03/rte__ethdev_8h.html#a300d75b583c1f5acfe5b162a5d8c0ac1

> 
> 
> __________________________________________________________________________________________________________________________________________________________________________________________
> 
> 
> Environment Details:
>
>  *  NIC used: Intel I225/I210
>  *  Hugepages configured: 1 GB
>  *  NUMA binding: --cpunodebind=0 --membind=0
>  *  OS: [Your Linux distribution, e.g., Ubuntu 20.04]
>  *  DPDK version: [Mention if known]
> 
> __________________________________________________________________________________________________________________________________________________________________________________________
> 
> 
> Could you please advise if any additional setup, configuration, or known limitations may be impacting the packet transmission?

This may be a wild suggestion from my side, but it pays to check whether link
status is "up" upon port start on both ends. One can use API [8] to do that.

[8] https://doc.dpdk.org/api-25.03/rte__ethdev_8h.html#ac05878578e4fd9ef3551d2c1c175ebe7

Thank you.


> 
> Thank you in advance for your support!
> 
> 
> Best regards,
> Gokul K R
> 
>  
> 
> 
>