[dpdk-users] Sequential UDP packets

[Pierre Laurent]

HI

Without much information , it is very hard to imagine what you are doing and what you are getting.

>From the packet numbers you provide, it looks like you are seeing all packets, and it is not a packet loss problem.

DPDK itself does not reorder the packets.
But your DPDK setup might be built from multiple path and transmit packets from multiple threads and /or multiple queues , or both, or over multiple interfaces.


If you are sure to use one single TX thread, one single TX queue, one single TX interface to transmit your packets with DPDK, then this cannot be a DPDK problem.

The problem can be on the receive side where you are using wireshark with some standard OS and standard driver. It is very frequent in standard OS and standard drivers to implement multiple RX queues (e.g. Windows, Ubuntu ...).  With such a config, packets with the same tuple5 (source IP, dest IP, source Port, dest Port, protocol  https://www.techopedia.com/definition/28190/5-tuple ) are not reordered and assigned to the same RX queue.

If you number your packets by changing one of the elements of the tuple 5, e.g. the destination udp  port, then RX packets will be sent to different RX queues, this standard   feature is known as receive-side-scaling (RSS)   https://docs.microsoft.com/en-us/windows-hardware/drivers/network/introduction-to-receive-side-scaling  . Then Wireshark would get the packets in any order, depending on polling strategies and priorities, rates and packet distributions in the different queues. There are options in most OS to set the number of queues, or disable RSS.

Alternatively, make sure your packets have all the same "tuple5", and if you want to put some sequential number, I suggest you do it in the UDP payload.

This response is a guess, because you provided NO information about your environment, your setup, any packet size, any packet rate, any packet dump nor investigations you already did.

Regards,

Pierre



________________________________
From: users <users-bounces at dpdk.org> on behalf of Sarvesh Verma <sarveshfwecverma79 at gmail.com>
Sent: Wednesday 13 November 2019 07:56
To: users at dpdk.org <users at dpdk.org>
Subject: [dpdk-users] Sequential UDP packets

Hey DPDK users,

Since last two months I'm struggling to generate my own sequential UDP
packets through DPDK. At receiving side my packets counts are matching but
are not in sequence in Wireshark.
Expected- 1,2,3,4,5,6,7,8,9,10.........
Getting-1,4,6,8,9,2,3,5,7,10........…

Hope anyone will reply soon.

Thank you
Sarvesh Verma