Configuring Receive/Transmit Ring Buffer Size - UG1739

By default receive and transmit ring buffers on X4 series adapters support 1024 descriptors. You can identify and reconfigure ring buffer sizes using the ethtool command:

• To identify the current ring size:

  ethtool -g <interface>

• To set the new transmit or receive ring size to value N:

  ethtool -G <interface> [rx N| tx N]

  The ring buffer size must be a value between 128 and 32768.

To change the default value for all AMD Solarflare interfaces, set the rx_ring or tx_ring option for the sfc net driver module. Add the setting either to the /etc/modprobe.conf file, or to a file with a .conf extension under the /etc/modprobe.d directory. For example:

options sfc rx_ring=4096
options sfc tx_ring=4096

You must reload the driver to enable the option changes:

modprobe -r sfc
modprobe sfc

You must then rebuild the initramfs to ensure the option changes persist after a reboot:

dracut -f