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dtaht / sch_cake

Out of tree build for the new cake qdisc
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sch_cake: Make gso-splitting configurable from userspace #103

Closed ldir-EDB0 closed 6 years ago

ldir-EDB0 commented 6 years ago

This patch restores cake's deployed behavior at line rate to always split gso, and makes gso splitting configurable from userspace.

running cake unlimited (unshaped) at 1gigE, local traffic:

no-split-gso bql limit: 131966 split-gso bql limit: ~42392-45420

On this 4 stream test splitting gso apart results in halving the observed interpacket latency at no loss in throughput.

Summary of tcp_nup test run 'gso-split' (at 2018-07-26 16:03:51.824728):

Ping (ms) ICMP : 0.83 0.81 ms 341 TCP upload avg : 235.43 235.39 Mbits/s 301 TCP upload sum : 941.71 941.56 Mbits/s 301 TCP upload::1 : 235.45 235.43 Mbits/s 271 TCP upload::2 : 235.45 235.41 Mbits/s 289 TCP upload::3 : 235.40 235.40 Mbits/s 288 TCP upload::4 : 235.41 235.40 Mbits/s 291

verses

Summary of tcp_nup test run 'no-split-gso' (at 2018-07-26 16:37:23.563960):

                       avg       median          # data pts

Ping (ms) ICMP : 1.67 1.73 ms 348 TCP upload avg : 234.56 235.37 Mbits/s 301 TCP upload sum : 938.24 941.49 Mbits/s 301 TCP upload::1 : 234.55 235.38 Mbits/s 285 TCP upload::2 : 234.57 235.37 Mbits/s 286 TCP upload::3 : 234.58 235.37 Mbits/s 274 TCP upload::4 : 234.54 235.42 Mbits/s 288

Signed-off-by: David S. Miller davem@davemloft.net

tohojo commented 6 years ago

Hmm, I was expecting Dave to just push this... :P