[dpdk-users] [dpdk-dev] rte_eth_rx bug? duplicate message bufs

Lavanya Jose lavanya.jose at gmail.com
Fri Aug 12 01:57:55 CEST 2016

Hi Avinash,

For me it turned out to be a bug with duplicate detection code rather than
with DPDK. The sequence numbers were wrapping over and I didn't have enough
random bits for the payload either.

- Lavanya

On Thu, Aug 11, 2016 at 4:53 PM Yeddula, Avinash <ayeddula at ciena.com> wrote:

> Hi All,
> I do have a similar issue, any response to the below email might help me
> as well.
> Thanks
> -Avinash
> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Lavanya Jose
> Sent: Monday, August 08, 2016 11:44 AM
> To: users at dpdk.org; dev at dpdk.org
> Subject: [dpdk-dev] rte_eth_rx bug? duplicate message bufs
> Hi,
> I was wondering if anyone on this list has come across this problem of
> rte_eth_rx_burst returning the same mbuf contents multiple times especially
> during congestion. I notice this problem after some number of calls to
> rte_eth_rx_burst when I set the nb_pkts argument to anything more than 5. I
> did confirm that the contents (random payloads) in the duplicate packets
> are identical.
> I looked at the corresponding ixgbe driver code that gets packets from the
> rx ring.
> <
> https://github.com/emmericp/dpdk/blob/e5b112e4c7a4d63f3131294e9611e4a892b75008/drivers/net/ixgbe/ixgbe_rxtx.c#L1595
> >
> It looks like the driver doesn't drop packets if an mbuf allocation fails.
> I'm not sure if this is the root cause of the bug I'm seeing?
> I'm also curious about whether I need to set rx_descs and tx_descs to 40
> when I'm setting up the Intel 82599 device? The datasheet says there's 40
> descriptors per TX queue though default values I've seen in code are much
> larger..
> Thanks,
> Lavanya

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