When you say you disabled flow control did you disable it on the interface that is dropping packets or the other end? You might try explicitly disabling it on the interface that is dropping packets, that in turn should enable per-queue drop instead of putting back-pressure onto the Rx FIFO.
With flow control disabled on the local port you should see rx_no_dma_resources start incrementing if the issue is that one of the Rx rings is not keeping up. - Alex On Fri, Sep 23, 2016 at 11:09 AM, Michał Purzyński <michalpurzyns...@gmail.com> wrote: > xoff was increasing so I disabled flow control. > > That's a HP DL360 Gen9 and lspci -vvv tells me cards are connected to x8 > link, speed is 5GT/s and ASPM is disabled. > > Other error counters are still zero. When I compared rx_packets and > rx_missed_errors it looks like a 38% (!!) packets are getting lost. > > Unfortunately HP documentation is a scam and they actively avoid publishing > motherboard layout. > > Any other place I could look for hints? > > > On Fri, Sep 23, 2016 at 7:01 PM, Alexander Duyck <alexander.du...@gmail.com> > wrote: >> >> On Fri, Sep 23, 2016 at 1:10 AM, Michał Purzyński >> <michalpurzyns...@gmail.com> wrote: >> > Hello. >> > >> > On my IDS workload with af_packet I can see rx_missed_errors growing >> > while >> > rx_no_buffer_count does not. Basically every other kind of rx_ error >> > counter is 0, including rx_no_dma_resources. It's an 82599 based card. >> > >> > I don't know what to think about that. I went through ixgbe source code >> > and >> > the 82599 datasheet and seems like rx_missed_error means a new packet >> > overwrote something already in the packet buffer (FIFO queue on the >> > card) >> > because there was no more space in it. >> > >> > Now, that would happen if there is no place to DMA packets into - but >> > that >> > counter does not grow. >> > >> > Could you point me to where should I be looking for a problem? >> > >> > -- >> > Michal Purzynski >> >> The Rx missed count will increment if you are not able to receive a >> packet because the Rx FIFO is full. If you are not seeing any >> rx_no_dma_resources problems it might indicate that the problem is not >> with providing the DMA resources, but a problem on the bus itself. >> You might want to double check the slot the device is connected to in >> order to guarantee that there is a x8 link that supports 5GT/s all the >> way through to the root complex. >> >> - Alex > > ------------------------------------------------------------------------------ _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
