[dpdk-users] Packet drop when using KNI sample application

Andriy Berestovskyy aber at semihalf.com
Thu Sep 22 10:07:44 CEST 2016

Hey Amit,
Regarding the pings. Try to set the same MAC on vEth as you have on
eth0 prior the unbind, i.e.:

# ifconfig vEth hw ether <eth0 MAC>

Regarding the logs. There are compile-time options to enable debugs in
PMDs. Please see config/common_base file for the complete list.

Not sure which driver you use, but for virtio-net you could try to
enable *_VIRTIO_DEBUG_RX/TX and then recompile the DPDK and the KNI


On Mon, Sep 19, 2016 at 9:59 AM, Amit Sharma <amit.sh1094 at gmail.com> wrote:
> Hi,
> While running the DPDK KNI sample application, we are facing packet drop
> after some time.
> *Setup:-*
> 1. 2 VMs configured using Ubuntu 14.04
> 2. eth0 of both VMs connected to each other, and able to ping
> *DPDK related setup:-*
> 1. 1st VM eth0 is bound with DPDK driver[bind=uio_pci_generic]
> 2. Insert the KNI module in Linux kernel[insmod rte_kni.ko].
> 3. Start the KNI application [*./build/kni -c 0x3 -n 4 -- -P -p 0x1
> --config="(0,0,1)"*].
> 4. Assign the ip address to vEth0 [*ifconfig vEth0*]
> 5. start the tcpdump on vEth0
> 6. From 2nd VM try to ping
> *Issue:- *
> ping works fine for around 400-500 packets(we reserved 2000 2MB hugepages).
> after that ping packet is never sent back to VM2
> on further investigation we found *rte_eth_tx_burst *always returns 0 when
> the problem occurs
> we are investigating it further, But before that any help is welcome
> on the side note, we have another issue with log levels, to investigate the
> above issue we were trying to enable the logs for PMD
> using the following code
> rte_set_log_type(RTE_LOGTYPE_PMD, 1);
> rte_set_log_level(RTE_LOG_DEBUG);
> during initialization we see some logs from PMD, But after that no logs
> during receive and transmission of packets, any idea why is that?
> Thanks
> Amit Sharma

Andriy Berestovskyy

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