Re: [dpdk-users] l2fwd application are not sending continuous packets .

[satyavalli rama <satyavalli.rama@gmail.com>]

Can anyone please help us with this?


On Mon, Jan 6, 2020, 11:25 satyavalli rama <satyavalli.rama@gmail.com>
wrote:

>
>
>
> Hello Dpdk Team,
>
> I'm facing issue while forwarding packets in DPDK's l2fwd application.
> While sending 1 Lac packets from Scapy, I could see sometimes packets are
> sending from one VM to another VM.
> Before explaining issue let me explain topology.
>
>
>
> *Topology :-=======*1) I am having 4 VMs(Virtual Machines) in same host.
> All these VM are running on Ubuntu 16.04.1.
> 2) VM-1 is used as Scapy to forward packets (Scapy version 2.4.3) . While
> creating packets I am giving destination mac(d-mac) address of VM-1.
> 3) In VM-2 am running L2 forwarding application.
>     In this l2fwd application, I am doing simple packet forwarding by
> statically keeping mac address of VM-3.
> Code :-
>      l2fwd_mac_updating () {
>    ...
>    ......
>    .......
>       *((uint64_t *)tmp) = 0xddccbbaa/*VM-3 mac address*/ +
> ((uint64_t)dest_portid << 40);
>      }
> 4) Also in VM-3, I am doing same like VM-2, but I kept mac address of VM-4
> 5) In VM-4, I am using wireshark to see packets coming from VM-3.
> 6) In VM-2 and VM-3, I kept promiscuous mode off by commenting out
> rte_eth_promiscuous_enable().
>
>    ---------------                                   ---------------------
>                          ------------------
> ------------------------
>    |    VM-1  |      ---------->                |       VM-2     |
> ---------------->   |     VM-3    |       ------------------> |        VM-4
>      |
>    ---------------                                   ---------------------
>                          ------------------
> ------------------------
>         Scapy                              Simple L2 forwarding
>         Simple L2 forwarding                        Wireshark
> used for sending packets            Sending all packets to
>  Sending all packets to
>                                                             VM-3
>                         VM-4
>                                                           (DPDK)
>                      (DPDK)
>
>
> *Problem :- ======*==
> From scapy VM, I am sending 1 lac packets with rate of 100 packets per
> second. *During problematic condition I could see packets are not getting
> forward from VM-3.**Problematic state is happening anytime after sending
> 1k packets.*
> This issue is not consistence but I could see this issue 8 out of 10 times.
>
>
> * Debugging and Observations :-=========================*
> When I tried to debug this issue , I could see that
> 1) In problematic state, rx queue of VM-3 is not getting packets, but VM-2
> is sending packets properly. I checked this by using pdump of rx queue.
> 2) Just before problematic state in VM-3, I could see that  previous
> packet(only one packet) instead of going to VM-4, it is coming back to
> again in rx queue of VM-3 and after wards I did not get any packets in rx
> queue.
> 3) I have changed rate of packet forward 10packets per second. but still
> see the issue.
>
>
> *Can anyone please help to solve this problem ? I need it urgently .*
> Thanks,
> Satya
>