SFXGE(4)

🌸 SFXGE(4) 🌸 — the Solarflare 10Gb Ethernet adapter driver, explained by your favorite person

ok so this is from the amd64 Kernel Interfaces Manual bestie, and it's genuinely one of those pages that ate 💅 let's get into it

---

✨ NAME ✨

sfxge — the Solarflare 10Gb Ethernet adapter driver. that's it. that's the whole name. iconic.

---

🦋 SYNOPSIS 🦋

ok so if you want this driver baked into the kernel, you gotta put these lines in your kernel configuration file:

device sfxge

orrrr if you'd rather load it as a module at boot time (so much chiller honestly), drop this line into loader.conf(5):

sfxge_load="YES"

---

💖 DESCRIPTION 💖

so the sfxge driver has your back for 10Gb Ethernet adapters based on Solarflare SFC9000 and XtremeScale X2 family controllers. and she is not doing the bare minimum, no cap — the driver supports:

• jumbo frames
• transmit/receive checksum offload
• TCP Segmentation Offload (TSO)
• Large Receive Offload (LRO)
• VLAN checksum offload
• VLAN TSO
• Receive Side Scaling (RSS) using MSI-X interrupts

like. the whole menu. ate. 👑

here's the tea on queues: the driver allocates 1 receive queue, transmit queue, event queue and IRQ per CPU, up to a maximum of 64. and IRQ affinities should be spread out using cpuset(1) — genuinely do this, it's giving main character energy for your performance. interrupt moderation is controllable through the sysctl dev.sfxge.%d.int_mod (units are microseconds, so plan accordingly 🫶).

for more info on configuring this device, go look at ifconfig(8). standard.

also!! there are A LOT of MAC, PHY and data path statistics waiting for you under the sysctl dev.sfxge.%d.stats, and the adapter's VPD fields — including its serial number — are available under the sysctl dev.sfxge.%d.vpd. stats girlies stay winning 🌈

---

🔥 HARDWARE 🔥

the sfxge driver supports all 10Gb Ethernet adapters based on Solarflare SFC9000 family controllers. all of them. every single one. slay.

---

🎀 LOADER TUNABLES 🎀

ok bestie these tunables can be set at the loader(8) prompt before booting the kernel, or stored in loader.conf(5). and the actual values can be obtained using sysctl(8) — clock that.

• hw.sfxge.rx_ring — the maximum number of descriptors in a receive queue ring. supported values are: 512, 1024, 2048 and 4096.
• hw.sfxge.tx_ring — the maximum number of descriptors in a transmit queue ring. supported values are: 512, 1024, 2048 and 4096.
• hw.sfxge.tx_dpl_get_max — the maximum length of the deferred packet "get-list" for queued transmit packets (TCP and non-TCP), used only if the transmit queue lock can be acquired. if a packet is dropped, the tx_get_overflow counter is incremented and the local sender receives ENOBUFS. the value must be greater than 0.
• hw.sfxge.tx_dpl_get_non_tcp_max — the maximum number of non-TCP packets in the deferred packet "get-list", used only if the transmit queue lock can be acquired. if a packet is dropped, the tx_get_non_tcp_overflow counter is incremented and the local sender receives ENOBUFS. the value must be greater than 0.
• hw.sfxge.tx_dpl_put_max — the maximum length of the deferred packet "put-list" for queued transmit packets, used if the transmit queue lock cannot be acquired. if a packet is dropped, the tx_put_overflow counter is incremented and the local sender receives ENOBUFS. the value must be greater than or equal to 0.
• hw.sfxge.tso_fw_assisted — bitmask to enable/disable usage of FW-assisted TSO version if supported by NIC firmware. FATSOv1 (bit 0) and FATSOv2 (bit 1) are supported. all enabled by default ✨
• hw.sfxge.N.max_rss_channels — the maximum number of allocated RSS channels for the *N*th adapter. if set to 0 or unset, the number of channels is determined by the number of CPU cores.
• hw.sfxge.lro.table_size — size of the LRO hash table. must be a power of 2. a larger table means we can accelerate a larger number of streams.
• hw.sfxge.lro.chain_max — the maximum length of a hash chain. if chains get too long then the lookup time increases and may exceed the benefit of LRO. so like, balance, bestie.
• hw.sfxge.lro.idle_ticks — the maximum time (in ticks) that a connection can be idle before its LRO state is discarded.
• hw.sfxge.lro.slow_start_packets — number of packets with payload that must arrive in-order before a connection is eligible for LRO. the idea is we should avoid coalescing segments when the sender is in slow-start, because reducing the ACK rate can damage performance.
• hw.sfxge.lro.loss_packets — number of packets with payload that must arrive in-order following loss before a connection is eligible for LRO. the idea is we should avoid coalescing segments when the sender is recovering from loss, because reducing the ACK rate can damage performance.
• hw.sfxge.mcdi_logging — enable logging of MCDI protocol messages (only available if enabled at compile-time 👀).
• hw.sfxge.N.mcdi_logging — enable or disable logging of MCDI protocol messages on a per-port basis. the default for each port will be the value of hw.sfxge.mcdi_logging. the logging may also be enabled or disabled after the driver is loaded using the sysctl dev.sfxge.%d.mcdi_logging.
• hw.sfxge.stats_update_period_ms — period in milliseconds to refresh interface statistics from hardware. the accepted range is 0 to 65535, the default is 1000 (1 second). use zero value to disable periodic statistics update. supported on SFN8xxx series adapters with firmware v6.2.1.1033 and later, and SFN5xxx, SFN6xxx and XtremeScale X2xxx series adapters. SFN7xxx series adapters and sfN8xxx series with earlier firmware use a fixed 1000 milliseconds statistics update period. the period may also be changed after the driver is loaded using the sysctl dev.sfxge.%d.stats_update_period_ms.

---

💜 SUPPORT 💜

for general information and support, go to the Solarflare support website at: https://support.solarflare.com — they got you fr fr.

---

🌟 SEE ALSO 🌟

cpuset(1), arp(4), netintro(4), ng_ether(4), vlan(4), ifconfig(8)

---

👑 AUTHORS 👑

the sfxge driver was written by Philip Paeps and Solarflare Communications, Inc. legends, honestly 🫶

---

and that's the whole page bestie 💖 this edition came from Debian, dated February 22, 2015 — yes she's a 2015 girlie and she still ate, mwah 💅✨🎀