1// SPDX-License-Identifier: GPL-2.0 2// Test of slow start when not application-limited, so that 3// the cwnd continues to grow. 4// In this variant, the receiver ACKs every other packet, 5// approximating standard delayed ACKs. 6 7// Set up config. To keep things simple, disable the 8// mechanism that defers sending in order to send bigger TSO packets. 9`./defaults.sh 10sysctl -q net.ipv4.tcp_tso_win_divisor=100` 11 12 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 13 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 14 +0 bind(3, ..., ...) = 0 15 +0 listen(3, 1) = 0 16 17 +.1 < S 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7> 18 +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8> 19 +.1 < . 1:1(0) ack 1 win 257 20 +0 accept(3, ..., ...) = 4 21 +0 setsockopt(4, SOL_SOCKET, SO_SNDBUF, [200000], 4) = 0 22 23 +0 write(4, ..., 30000) = 30000 24 +0 > P. 1:10001(10000) ack 1 25 +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }% 26 27+.105 < . 1:1(0) ack 2001 win 257 28 +0 > P. 10001:14001(4000) ack 1 29 30+.005 < . 1:1(0) ack 4001 win 257 31 +0 > P. 14001:18001(4000) ack 1 32 33+.005 < . 1:1(0) ack 6001 win 257 34 +0 > P. 18001:22001(4000) ack 1 35 36+.005 < . 1:1(0) ack 8001 win 257 37 +0 > P. 22001:26001(4000) ack 1 38 39+.005 < . 1:1(0) ack 10001 win 257 40 +0 > P. 26001:30001(4000) ack 1 41 42 +0 %{ assert tcpi_snd_cwnd == 20, tcpi_snd_cwnd }% 43