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SUME(4) FreeBSD Kernel Interfaces Manual SUME(4)
NAME
sume - NetFPGA SUME 4x10Gb Ethernet driver
SYNOPSIS
To compile this driver into the kernel, place the following lines in your
kernel configuration file:
device sume
Alternatively, to load the driver as a module at boot time, place the
following line in loader.conf(5):
if_sume_load="YES"
DESCRIPTION
The sume driver provides support for NetFPGA SUME Virtex-7 FPGA
Development Board with the reference NIC bitstream loaded onto it. The
HDL design for the reference NIC project uses the RIFFA based DMA engine
to communicate with the host machine over PCIe. Every packet is
transmitted to / from the board via a single DMA transaction, taking up
to two or three interrupts per one transaction which yields low
performance.
There is no support for Jumbo frames as the hardware is capable of
dealing only with frames with maximum size of 1514 bytes. The hardware
does not support multicast filtering, provides no checksums, and offers
no other offloading.
SEE ALSO
arp(4), netgraph(4), netintro(4), ng_ether(4), vlan(4), ifconfig(8)
AUTHORS
The Linux sume driver was originally written by Bjoern A. Zeeb. The
FreeBSD version and this manual page were written by Denis Salopek as a
GSoC project. More information about the project can be found here:
https://wiki.freebsd.org/SummerOfCode2020Projects/NetFPGA_SUME_Driver
BUGS
The reference NIC hardware design provides no mechanism for quiescing
inbound traffic from interfaces configured as DOWN. All packets from
administratively disabled interfaces are transferred to main memory,
leaving the driver with the task of dropping such packets, thus consuming
PCI bandwidth, interrupts and CPU cycles in vain.
Pre-built FPGA bitstream from the NetFPGA project may not work correctly.
At higher RX packet rates, the newly incoming packets can overwrite the
ones in an internal FIFO so the packets would arrive in main memory
corrupted, until a physical reset of the board.
Occasionally, the driver can get stuck in a non-IDLE TX state due to a
missed interrupt. The driver includes a watchdog function which monitors
for such a condition and resets the board automatically. For more
details, visit the NetFPGA SUME project site.
FreeBSD 14.0-RELEASE-p11 August 30, 2020 FreeBSD 14.0-RELEASE-p11