Merge branch 'net-support-ipv4-big-tcp'
Xin Long says:
====================
net: support ipv4 big tcp
This is similar to the BIG TCP patchset added by Eric for IPv6:
https://lwn.net/Articles/895398/
Different from IPv6, IPv4 tot_len is 16-bit long only, and IPv4 header
doesn't have exthdrs(options) for the BIG TCP packets' length. To make
it simple, as David and Paolo suggested, we set IPv4 tot_len to 0 to
indicate this might be a BIG TCP packet and use skb->len as the real
IPv4 total length.
This will work safely, as all BIG TCP packets are GSO/GRO packets and
processed on the same host as they were created; There is no padding
in GSO/GRO packets, and skb->len - network_offset is exactly the IPv4
packet total length; Also, before implementing the feature, all those
places that may get iph tot_len from BIG TCP packets are taken care
with some new APIs:
Patch 1 adds some APIs for iph tot_len setting and getting, which are
used in all these places where IPv4 BIG TCP packets may reach in Patch
2-7, Patch 8 adds a GSO_TCP tp_status for af_packet users, and Patch 9
add new netlink attributes to make IPv4 BIG TCP independent from IPv6
BIG TCP on configuration, and Patch 10 implements this feature.
Note that the similar change as in Patch 2-6 are also needed for IPv6
BIG TCP packets, and will be addressed in another patchset.
The similar performance test is done for IPv4 BIG TCP with 25Gbit NIC
and 1.5K MTU:
No BIG TCP:
for i in {1..10}; do netperf -t TCP_RR -H 192.168.100.1 -- -r80000,80000 -O MIN_LATENCY,P90_LATENCY,P99_LATENCY,THROUGHPUT|tail -1; done
168 322 337 3776.49
143 236 277 4654.67
128 258 288 4772.83
171 229 278 4645.77
175 228 243 4678.93
149 239 279 4599.86
164 234 268 4606.94
155 276 289 4235.82
180 255 268 4418.95
168 241 249 4417.82
Enable BIG TCP:
ip link set dev ens1f0np0 gro_ipv4_max_size 128000 gso_ipv4_max_size 128000
for i in {1..10}; do netperf -t TCP_RR -H 192.168.100.1 -- -r80000,80000 -O MIN_LATENCY,P90_LATENCY,P99_LATENCY,THROUGHPUT|tail -1; done
161 241 252 4821.73
174 205 217 5098.28
167 208 220 5001.43
164 228 249 4883.98
150 233 249 4914.90
180 233 244 4819.66
154 208 219 5004.92
157 209 247 4999.78
160 218 246 4842.31
174 206 217 5080.99
Thanks for the feedback from Eric and David Ahern.
====================
Link: https://lore.kernel.org/r/cover.1674921359.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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