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

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

Thanks Stephen,
We've tried to debug issue in couple of ways, please correct us whether
these approaches or right not wrong?
1. We have increased the MAX_PKT_BURST from 32 to 64 and
MEMEPOOL_CAHCE_SIZE 256 to 512
2. Keeping IGB_UIO as the only driver module.
3. Resetting the RX queues.
But still we are seeing the issue, as mentioned above========
> > * 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.


On Thu, Jan 9, 2020, 11:42 Stephen Hemminger <stephen@networkplumber.org>
wrote:

> On Thu, 9 Jan 2020 07:25:45 +0530
> satyavalli rama <satyavalli.rama@gmail.com> wrote:
>
> > 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
> > >
>
> Sorry, you need to dig inside the forwarding application and instrument
> what is coming in and how packets are being processed. You usually can't
> treat DPDK as a black box.
>