[dpdk-dev] Inconsistent statistics counters for pmd_i40e

[Arnon Warshavsky]

Hi Eimear,

I just experienced the same problem with firmware versions 4.23 and 4.33
(dpdk 2.0). Did not get to try the latest which is 4.5.
Looking at the code, I don't see that this counter is being read any
differently than its peer counters and I suspect the nic itself.
Can you tell which firmware version you were using?

thanks
/Arnon

On Mon, Oct 19, 2015 at 2:43 PM, Eimear Morrissey <
eimear.morrissey at ie.ibm.com> wrote:

>
>
> Hi,
>
> I'm having issues measuring packets dropped at the NIC in both the 2.0.0
> and 2.1.0 versions of DPDK on an X710 Intel NIC.
>
> In dpdk-2.0.0
> Using rte_eth_xstats the rx_packets and rx_bytes counters increase as
> expected, however rx_missed_errors is always 0 even if a sleep statement is
> added between calls to rte_eth_rx_burst. However changing the coremask so
> the application is running on a different socket than the card will cause
> rx_missed_errors to increment for a limited amount of time and then stop.
> Using rte_eth_stats, ipackets is incremented on packet receipt but the
> q_ipackets and q_errors arrays remain zero. Even crossing sockets seems to
> have no effect on q_errors.
>
> In dpdk-2.1.0 the behaviour is the same as above, except that the number of
> fields returned by rte_eth_xstats_get is reduced (no rx_missed errors at
> all) so running on a different socket no longer has any noticeable effect
> on the stats.
>
> My understanding from the API manual is that the rte_eth_stats q_errors
> array should count the packets missed because software isn't polling fast
> enough, but that doesn't seem to be the case? Is there a standard DPDK way
> to check this? The application is a forwarding one so there's no other way
> to estimate drop except through NIC rx.
>
> Thanks,
> Eimear
>



-- 

*Arnon Warshavsky*
*Qwilt | work: +972-72-2221634 | mobile: +972-50-8583058 | arnon at qwilt.com
<arnon at qwilt.com>*