Basically, this is automatic rx zero copy when feasible. TCP payload is
DMA'd directly into the userspace buffer described by the uio submitted
in soreceive by an application.
- Works with sockets that are being handled by the TCP offload engine
of a T4 chip (you need t4_tom.ko module loaded after cxgbe, and an
"ifconfig +toe" on the cxgbe interface).
- Does not require any modification to the application.
- Not enabled by default. Use hw.t4nex.<X>.toe.ddp="1" to enable it.
- Stateful TCP offload drivers for Terminator 3 and 4 (T3 and T4) ASICs.
These are available as t3_tom and t4_tom modules that augment cxgb(4)
and cxgbe(4) respectively. The cxgb/cxgbe drivers continue to work as
usual with or without these extra features.
- iWARP driver for Terminator 3 ASIC (kernel verbs). T4 iWARP in the
works and will follow soon.
Build-tested with make universe.
30s overview
============
What interfaces support TCP offload? Look for TOE4 and/or TOE6 in the
capabilities of an interface:
# ifconfig -m | grep TOE
Enable/disable TCP offload on an interface (just like any other ifnet
capability):
# ifconfig cxgbe0 toe
# ifconfig cxgbe0 -toe
Which connections are offloaded? Look for toe4 and/or toe6 in the
output of netstat and sockstat:
# netstat -np tcp | grep toe
# sockstat -46c | grep toe
Reviewed by: bz, gnn
Sponsored by: Chelsio communications.
MFC after: ~3 months (after 9.1, and after ensuring MFC is feasible)
- Device configuration via plain text config file. Also able to operate
when not attached to the chip as the master driver.
- Generic "work request" queue that serves as the base for both ctrl and
ofld tx queues.
- Generic interrupt handler routine that can process any event on any
kind of ingress queue (via a dispatch table).
- A couple of new driver ioctls. cxgbetool can now install a firmware
to the card ("loadfw" command) and can read the card's memory
("memdump" and "tcb" commands).
- Lots of assorted information within dev.t4nex.X.misc.* This is
primarily for debugging and won't show up in sysctl -a.
- Code to manage the L2 tables on the chip.
- Updates to cxgbe(4) man page to go with the tunables that have changed.
- Updates to the shared code in common/
- Updates to the driver-firmware interface (now at fw 1.4.16.0)
MFC after: 1 month
filters working. (All other filters - switch without L2 info rewrite,
steer, and drop - were already fully-functional).
Some contrived examples of "switch" filters with L2 rewriting:
# cxgbetool t4nex0 iport 0 dport 80 action switch vlan +9 eport 3
Intercept all packets received on physical port 0 with TCP port 80 as
destination, insert a vlan tag with VID 9, and send them out of port 3.
# cxgbetool t4nex0 sip 192.168.1.1/32 ivlan 5 action switch \
vlan =9 smac aa:bb:cc:dd:ee:ff eport 0
Intercept all packets (received on any port) with source IP address
192.168.1.1 and VLAN id 5, rewrite the VLAN id to 9, rewrite source mac
to aa:bb:cc:dd:ee:ff, and send it out of port 0.
MFC after: 1 week
Reference code that shows how to get a packet's timestamp out of
cxgbe(4). Disabled by default because we don't have a standard way
today to pass this information up the stack.
The timestamp is 60 bits wide and each increment represents 1 tick of
the T4's core clock. As an example, the timestamp granularity is ~4.4ns
for this card:
# sysctl dev.t4nex.0.core_clock
dev.t4nex.0.core_clock: 228125
MFC after: 1 week
