Re: [dpdk-dev] pktgen rx errors with intel 82599

["Wiles, Keith" <keith.wiles@intel.com>]

Hi Matt,

On 3/14/15, 8:47 AM, "Wiles, Keith" <keith.wiles@intel.com> wrote:

>Hi Matt
>
>On 3/13/15, 3:49 PM, "Matt Smith" <mgsmith@netgate.com> wrote:
>
>>
>>Hi,
>>
>>I¹ve been using DPDK pktgen 2.8.0 (built against DPDK 1.8.0 libraries) to
>>send traffic on a server using an Intel 82599 (X520-2). Traffic gets sent
>>out port 1 through another server which also an Intel 82599 installed and
>>is forwarded back into port 0. When I send using a single source and
>>destination IP address, this works fine and packets arrive on port 0 at
>>close to the maximum line rate.
>>
>>If I change port 1 to range mode and send traffic from a range of source
>>IP addresses to a single destination IP address, for a second or two the
>>display indicates that some packets were received on port 0 but then the
>>rate of received packets on the display goes to 0 and all incoming
>>packets on port 0 are registered as rx errors.
>>
>>The server that traffic is being forwarded through is running the
>>ip_pipeline example app. I ruled this out as the source of the problem by
>>sending directly from port 1 to port 0 of the pktgen box. The issue still
>>occurs when the traffic is not being forwarded through the other box.
>>Since ip_pipeline is able to receive the packets and forward them without
>>getting rx errors and it¹s running with the same model of NIC as pktgen
>>is using, I checked to see if there were any differences in
>>initialization of the rx port between ip_pipeline and pktgen. I noticed
>>that pktgen has a setting that ip_pipeline doesn't:
>>
>>const struct rte_eth_conf port_conf = {
>>    .rxmode = {
>>    .mq_mode = ETH_MQ_RX_RSS,
>>
>>If I comment out the .mq_mode setting and rebuild pktgen, the problem no
>>longer occurs and I now receive packets on port 0 at near line rate when
>>testing from a range of source addresses.
>>
>>I recall reading in the past that if a receive queue fills up on an 82599
>>, that receiving stalls for all of the other queues and no more packets
>>can be received. Could that be happening with pktgen? Is there any
>>debugging I can do to help track it down?
>
>I have seen this problem on some platforms a few times and it looks like
>you may have found a possible solution to the problem. I will have to look
>into the change and see if this is the problem, but it does seem to
>suggest this may be the issue. When the port gets into this state the port
>receives the number mbufs matching the number of descriptors and the rest
>are Œmissed¹ frames at the wire. The RX counter is the number of missed
>frames.
>
>Thanks for the input
>++Keith

I added code to hopefully setup the correct RX/TX conf values. The HEAD of
the Pktgen-DPDK v2.8.4 should build and work with DPDK 1.8.0 or 2.0.0-rc1.
I did still see some RX errors and reduced bit rate, but the traffic does
not stop on my machine. Please give version 2.8.4 a try and let me know if
you still see problems.

Regards,
++Keith
>>
>>The command line I have been launching pktgen with is:
>>
>>pktgen -c f -n 3 -m 512 -- -p 0x3 -P -m 1.0,2.1
>>
>>Thanks,
>>
>>-Matt Smith
>>
>>
>>
>>
>>
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