Re: [dpdk-users] packet drops seen once the no of rxd pkts reach the ring size

[Gaurav Bansal <zeebee48@gmail.com>]

Thanks Stephen for the reply. I am planning to try that but that will
require some major changes & lot more time, as this library is tightly
integrated with our code base. Meanwhile please let me know if there is
anything that can be tried on 16.04 itself.
thanks,
gaurav

On Thu, Sep 26, 2019 at 10:46 AM Stephen Hemminger <
stephen@networkplumber.org> wrote:

> On Thu, 26 Sep 2019 10:45:03 +0530
> Gaurav Bansal <zeebee48@gmail.com> wrote:
>
> > any suggestions here ?
> >
> > On Wed, Sep 25, 2019 at 4:09 PM Gaurav Bansal <zeebee48@gmail.com>
> wrote:
> >
> > > Hi all,
> > > I am using dpdk 16.04 library to process the packets on a vmware vm
> (say
> > > vm1). The traffic is sent through a client machine using apache bench.
> I am
> > > observing an issue when the number of packets reaching the vmxnet3
> > > interface reaches the descriptor ring size (set to 2048). Till 2048
> all the
> > > packets correctly reach the 'vmxnet3_recv_pkts' function.
> > >
> > > But as the number of packets received reaches 2048, i start seeing some
> > > retransmissions on the client side (as shown by tcpdump on client
> side).
> > > Then i captured the packets on the esx host destined to vm1 and it
> shows
> > > that all the original packets as well as the corresponding
> retransmissions
> > > are reaching vm1. But somehow these packets fail to reach till
> > > 'vmxnet3_recv_pkts' function (this was found by putting the breakpoint
> in
> > > 'vmxnet3_recv_pkts' function and dumping the packet contents, which
> showed
> > > that some packets don't reach here).
> > >
> > > Now 'vmxnet3_recv_pkts' is the first function which reads the packets
> from
> > > the descriptor ring and as the packets are not reaching till here, i
> am not
> > > sure on how to debug this further. Possibly some issues related to the
> ring
> > > initialization.... I enabled the init & RX logs for vmxnet3, but i
> don't
> > > see any error logs as well. I also tried looking at rxq stats and it
> shows
> > > 0 all the time :
> > > (gdb) p rxq->stats
> > > $1 = {drop_total = 0, drop_err = 0, drop_fcs = 0, rx_buf_alloc_failure
> = 0}
> > >
> > > Can anyone please provide some clues on how to debug this further ? Are
> > > there any known issues related to this which have been fixed post 16.04
> > > version ?
> > > thanks,
> > > gaurav
> > >
>
> Try a newer version of DPDK first.
>