[dpdk-users] occasionally traffic stalls due to rx and tx descriptor not available

Amarnath Nallapothula Amarnath.Nallapothula at riverbed.com
Thu Jul 5 13:34:58 CEST 2018

Hi Experts,

I am testing performance of my dpdk based application which forwards packets from port 1 to port 2 of 40G NIC card and via versa.Occasionally we see that packets rx and tx stops on one of the port. I looked through the dpdk’s fm10k driver’s code and found out that this could happen if rx/tx descriptors are not available.

To improve performance, I am using RSS functionality and created five rx and tx queue. Dedicated lcores are assigned to forward packets from port1 queue 0 to port2 queue 0 and via versa.

During port initialization rx_queue is initialized with 128 Rx ring descriptor size and tx_queue  is initialized 512 Tx ring descriptor. Threshold values are left default.

I have few queries here:

  1.  Is above initialization value for rx and tx descriptor is good for each queue for given port.
  2.  Under what conditions rx and tx descriptor gets exhausted?
  3.  Any suggestion or information you can provide to debug this issue?


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