3 Replies Latest reply on Dec 31, 2014 1:08 PM by mlehr

    RX ring parameter

      Hello,

       

      I am working on trying to obtain near line rate for a ConnectX-3 adapter (MCX354A). I am also trying to minimize or eliminate packet loss for high-throughput UDP transfers. One parameter that I have found makes a large difference is the setting for the receive ring buffer size. The default value was 1024, which I have increased to 8192:

       

      # ethtool -g eth2
      Ring parameters for eth2:
      Pre-set maximums:
      RX:        8192
      RX Mini:    0
      RX Jumbo:    0
      TX:        8192
      Current hardware settings:
      RX:        8192
      RX Mini:    0
      RX Jumbo:    0
      TX:        8192

       

      To what exactly does that number correspond? Is it a number of 4KB memory buffers (for 4KB pages)? Does each entry correspond to the current MTU? Basically, I am trying to determine how many packets of a given size can fit in the receive ring.

       

      Regards,

      Thomas