On 7/2/19 3:09 PM, brakmo wrote: > Adds support for fq's Earliest Departure Time to HBM (Host Bandwidth > Manager). Includes a new BPF program supporting EDT, and also updates > corresponding programs. > > It will drop packets with an EDT of more than 500us in the future > unless the packet belongs to a flow with less than 2 packets in flight. > This is done so each flow has at least 2 packets in flight, so they > will not starve, and also to help prevent delayed ACK timeouts. > > It will also work with ECN enabled traffic, where the packets will be > CE marked if their EDT is more than 50us in the future. > > The table below shows some performance numbers. The flows are back to > back RPCS. One server sending to another, either 2 or 4 flows. > One flow is a 10KB RPC, the rest are 1MB RPCs. When there are more > than one flow of a given RPC size, the numbers represent averages. > > The rate limit applies to all flows (they are in the same cgroup). > Tests ending with "-edt" ran with the new BPF program supporting EDT. > Tests ending with "-hbt" ran on top HBT qdisc with the specified rate > (i.e. no HBM). The other tests ran with the HBM BPF program included > in the HBM patch-set. > > EDT has limited value when using DCTCP, but it helps in many cases when > using Cubic. It usually achieves larger link utilization and lower > 99% latencies for the 1MB RPCs. > HBM ends up queueing a lot of packets with its default parameter values, > reducing the goodput of the 10KB RPCs and increasing their latency. Also, > the RTTs seen by the flows are quite large. > > Aggr 10K 10K 10K 1MB 1MB 1MB > Limit rate drops RTT rate P90 P99 rate P90 P99 > Test rate Flows Mbps % us Mbps us us Mbps ms ms > -------- ---- ----- ---- ----- --- ---- ---- ---- ---- ---- ---- > cubic 1G 2 904 0.02 108 257 511 539 647 13.4 24.5 > cubic-edt 1G 2 982 0.01 156 239 656 967 743 14.0 17.2 > dctcp 1G 2 977 0.00 105 324 408 744 653 14.5 15.9 > dctcp-edt 1G 2 981 0.01 142 321 417 811 660 15.7 17.0 > cubic-htb 1G 2 919 0.00 1825 40 2822 4140 879 9.7 9.9 > > cubic 200M 2 155 0.30 220 81 532 655 74 283 450 > cubic-edt 200M 2 188 0.02 222 87 1035 1095 101 84 85 > dctcp 200M 2 188 0.03 111 77 912 939 111 76 325 > dctcp-edt 200M 2 188 0.03 217 74 1416 1738 114 76 79 > cubic-htb 200M 2 188 0.00 5015 8 14ms 15ms 180 48 50 > > cubic 1G 4 952 0.03 110 165 516 546 262 38 154 > cubic-edt 1G 4 973 0.01 190 111 1034 1314 287 65 79 > dctcp 1G 4 951 0.00 103 180 617 905 257 37 38 > dctcp-edt 1G 4 967 0.00 163 151 732 1126 272 43 55 > cubic-htb 1G 4 914 0.00 3249 13 7ms 8ms 300 29 34 > > cubic 5G 4 4236 0.00 134 305 490 624 1310 10 17 > cubic-edt 5G 4 4865 0.00 156 306 425 759 1520 10 16 > dctcp 5G 4 4936 0.00 128 485 221 409 1484 7 9 > dctcp-edt 5G 4 4924 0.00 148 390 392 623 1508 11 26 > > v1 -> v2: Incorporated Andrii's suggestions > v2 -> v3: Incorporated Yonghong's suggestions > v3 -> v4: Removed credit update that is not needed > > Signed-off-by: Lawrence Brakmo <bra...@fb.com>
Acked-by: Yonghong Song <y...@fb.com>
