From e874be276ee4f22de2bdf3c3a876a41a71c3207f Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Wed, 11 Sep 2024 20:52:42 -0400 Subject: [PATCH] selftests/net: packetdrill: import tcp/slow_start Same import process as previous tests. Also add CONFIG_NET_SCH_FQ to config, as one test uses that. Same test process as previous tests. Both with and without debug mode. Recording the steps once: make mrproper vng --build \ --config tools/testing/selftests/net/packetdrill/config \ --config kernel/configs/debug.config vng -v --run . --user root --cpus 4 -- \ make -C tools/testing/selftests TARGETS=net/packetdrill run_tests Link: https://github.com/linux-netdev/nipa/wiki/How-to-run-netdev-selftests-CI-style#how-to-build Signed-off-by: Willem de Bruijn Acked-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20240912005317.1253001-4-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski --- .../testing/selftests/net/packetdrill/config | 1 + ...tcp_slow_start_slow-start-ack-per-1pkt.pkt | 56 +++++++++++++++++ ...tart_slow-start-ack-per-2pkt-send-5pkt.pkt | 33 ++++++++++ ...tart_slow-start-ack-per-2pkt-send-6pkt.pkt | 34 ++++++++++ ...tcp_slow_start_slow-start-ack-per-2pkt.pkt | 42 +++++++++++++ ...tcp_slow_start_slow-start-ack-per-4pkt.pkt | 35 +++++++++++ .../tcp_slow_start_slow-start-after-idle.pkt | 39 ++++++++++++ ...slow_start_slow-start-after-win-update.pkt | 50 +++++++++++++++ ...t_slow-start-app-limited-9-packets-out.pkt | 38 +++++++++++ .../tcp_slow_start_slow-start-app-limited.pkt | 36 +++++++++++ ..._slow_start_slow-start-fq-ack-per-2pkt.pkt | 63 +++++++++++++++++++ 11 files changed, 427 insertions(+) create mode 100644 tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-1pkt.pkt create mode 100644 tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-2pkt-send-5pkt.pkt create mode 100644 tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-2pkt-send-6pkt.pkt create mode 100644 tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-2pkt.pkt create mode 100644 tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-4pkt.pkt create mode 100644 tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-after-idle.pkt create mode 100644 tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-after-win-update.pkt create mode 100644 tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-app-limited-9-packets-out.pkt create mode 100644 tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-app-limited.pkt create mode 100644 tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-fq-ack-per-2pkt.pkt diff --git a/tools/testing/selftests/net/packetdrill/config b/tools/testing/selftests/net/packetdrill/config index a7877819081f..0237ed98f3c0 100644 --- a/tools/testing/selftests/net/packetdrill/config +++ b/tools/testing/selftests/net/packetdrill/config @@ -3,6 +3,7 @@ CONFIG_HZ_1000=y CONFIG_HZ=1000 CONFIG_NET_NS=y CONFIG_NET_SCH_FIFO=y +CONFIG_NET_SCH_FQ=y CONFIG_PROC_SYSCTL=y CONFIG_SYN_COOKIES=y CONFIG_TCP_CONG_CUBIC=y diff --git a/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-1pkt.pkt b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-1pkt.pkt new file mode 100644 index 000000000000..795c476d222d --- /dev/null +++ b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-1pkt.pkt @@ -0,0 +1,56 @@ +// SPDX-License-Identifier: GPL-2.0 +// Test of slow start when not application-limited, so that +// the cwnd continues to grow. +// In this variant, the receiver ACKs every packet. + +// Set up config. To keep things simple, disable the +// mechanism that defers sending in order to send bigger TSO packets. +`./defaults.sh +sysctl -q net.ipv4.tcp_tso_win_divisor=100` + + 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 + +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 + +0 bind(3, ..., ...) = 0 + +0 listen(3, 1) = 0 + + +.1 < S 0:0(0) win 32792 + +0 > S. 0:0(0) ack 1 + +.1 < . 1:1(0) ack 1 win 257 + +0 accept(3, ..., ...) = 4 + +0 setsockopt(4, SOL_SOCKET, SO_SNDBUF, [200000], 4) = 0 + + +0 write(4, ..., 30000) = 30000 + +0 > P. 1:10001(10000) ack 1 + +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }% + ++.105 < . 1:1(0) ack 1001 win 257 + +0 > P. 10001:12001(2000) ack 1 + + +0 < . 1:1(0) ack 2001 win 257 + +0 > P. 12001:14001(2000) ack 1 + ++.005 < . 1:1(0) ack 3001 win 257 + +0 > P. 14001:16001(2000) ack 1 + + +0 < . 1:1(0) ack 4001 win 257 + +0 > P. 16001:18001(2000) ack 1 + ++.005 < . 1:1(0) ack 5001 win 257 + +0 > P. 18001:20001(2000) ack 1 + + +0 < . 1:1(0) ack 6001 win 257 + +0 > P. 20001:22001(2000) ack 1 + ++.005 < . 1:1(0) ack 7001 win 257 + +0 > P. 22001:24001(2000) ack 1 + + +0 < . 1:1(0) ack 8001 win 257 + +0 > P. 24001:26001(2000) ack 1 + ++.005 < . 1:1(0) ack 9001 win 257 + +0 > P. 26001:28001(2000) ack 1 + + +0 < . 1:1(0) ack 10001 win 257 + +0 > P. 28001:30001(2000) ack 1 + + +0 %{ assert tcpi_snd_cwnd == 20, tcpi_snd_cwnd }% diff --git a/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-2pkt-send-5pkt.pkt b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-2pkt-send-5pkt.pkt new file mode 100644 index 000000000000..9212ae1fd0f2 --- /dev/null +++ b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-2pkt-send-5pkt.pkt @@ -0,0 +1,33 @@ +// SPDX-License-Identifier: GPL-2.0 +// Test of slow start when an outstanding flight of packets is +// less than the current cwnd, and not big enough to bump up cwnd. +// +// In this variant, the receiver ACKs every other packet, +// approximating standard delayed ACKs. + +// Set up config. +`./defaults.sh` + + 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 + +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 + +0 bind(3, ..., ...) = 0 + +0 listen(3, 1) = 0 + + +0 < S 0:0(0) win 32792 + +0 > S. 0:0(0) ack 1 + +0 < . 1:1(0) ack 1 win 257 + +0 accept(3, ..., ...) = 4 + +// Only send 5 packets. + +0 write(4, ..., 5000) = 5000 + +0 > P. 1:5001(5000) ack 1 + +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }% + + +0 < . 1:1(0) ack 2001 win 257 + +0 %{ assert tcpi_snd_cwnd == 10, 'cwnd=%d' % tcpi_snd_cwnd }% + + +0 < . 1:1(0) ack 4001 win 257 + +0 %{ assert tcpi_snd_cwnd == 10, 'cwnd=%d' % tcpi_snd_cwnd }% + + +0 < . 1:1(0) ack 5001 win 257 + +0 %{ assert tcpi_snd_cwnd == 10, 'cwnd=%d' % tcpi_snd_cwnd }% diff --git a/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-2pkt-send-6pkt.pkt b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-2pkt-send-6pkt.pkt new file mode 100644 index 000000000000..416c901ddf51 --- /dev/null +++ b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-2pkt-send-6pkt.pkt @@ -0,0 +1,34 @@ +// SPDX-License-Identifier: GPL-2.0 +// Test of slow start when an outstanding flight of packets is +// less than the current cwnd, but still big enough that in slow +// start we want to increase our cwnd a little. +// +// In this variant, the receiver ACKs every other packet, +// approximating standard delayed ACKs. + +// Set up config. +`./defaults.sh` + + 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 + +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 + +0 bind(3, ..., ...) = 0 + +0 listen(3, 1) = 0 + + +0 < S 0:0(0) win 32792 + +0 > S. 0:0(0) ack 1 + +0 < . 1:1(0) ack 1 win 257 + +0 accept(3, ..., ...) = 4 + +// Only send 6 packets. + +0 write(4, ..., 6000) = 6000 + +0 > P. 1:6001(6000) ack 1 + +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }% + + +0 < . 1:1(0) ack 2001 win 257 + +0 %{ assert tcpi_snd_cwnd == 12, 'cwnd=%d' % tcpi_snd_cwnd }% + + +0 < . 1:1(0) ack 4001 win 257 + +0 %{ assert tcpi_snd_cwnd == 12, 'cwnd=%d' % tcpi_snd_cwnd }% + + +0 < . 1:1(0) ack 6001 win 257 + +0 %{ assert tcpi_snd_cwnd == 12, 'cwnd=%d' % tcpi_snd_cwnd }% diff --git a/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-2pkt.pkt b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-2pkt.pkt new file mode 100644 index 000000000000..a894b7d4559c --- /dev/null +++ b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-2pkt.pkt @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0 +// Test of slow start when not application-limited, so that +// the cwnd continues to grow. +// In this variant, the receiver ACKs every other packet, +// approximating standard delayed ACKs. + +// Set up config. To keep things simple, disable the +// mechanism that defers sending in order to send bigger TSO packets. +`./defaults.sh +sysctl -q net.ipv4.tcp_tso_win_divisor=100` + + 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 + +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 + +0 bind(3, ..., ...) = 0 + +0 listen(3, 1) = 0 + + +.1 < S 0:0(0) win 32792 + +0 > S. 0:0(0) ack 1 + +.1 < . 1:1(0) ack 1 win 257 + +0 accept(3, ..., ...) = 4 + +0 setsockopt(4, SOL_SOCKET, SO_SNDBUF, [200000], 4) = 0 + + +0 write(4, ..., 30000) = 30000 + +0 > P. 1:10001(10000) ack 1 + +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }% + ++.105 < . 1:1(0) ack 2001 win 257 + +0 > P. 10001:14001(4000) ack 1 + ++.005 < . 1:1(0) ack 4001 win 257 + +0 > P. 14001:18001(4000) ack 1 + ++.005 < . 1:1(0) ack 6001 win 257 + +0 > P. 18001:22001(4000) ack 1 + ++.005 < . 1:1(0) ack 8001 win 257 + +0 > P. 22001:26001(4000) ack 1 + ++.005 < . 1:1(0) ack 10001 win 257 + +0 > P. 26001:30001(4000) ack 1 + + +0 %{ assert tcpi_snd_cwnd == 20, tcpi_snd_cwnd }% diff --git a/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-4pkt.pkt b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-4pkt.pkt new file mode 100644 index 000000000000..065fae9e9abd --- /dev/null +++ b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-ack-per-4pkt.pkt @@ -0,0 +1,35 @@ +// SPDX-License-Identifier: GPL-2.0 +// Test of slow start when not application-limited, so that +// the cwnd continues to grow. +// In this variant, the receiver sends one ACK per 4 packets. + +// Set up config. To keep things simple, disable the +// mechanism that defers sending in order to send bigger TSO packets. +`./defaults.sh +sysctl -q net.ipv4.tcp_tso_win_divisor=100` + + 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 + +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 + +0 bind(3, ..., ...) = 0 + +0 listen(3, 1) = 0 + + +.1 < S 0:0(0) win 32792 + +0 > S. 0:0(0) ack 1 + +.1 < . 1:1(0) ack 1 win 257 + +0 accept(3, ..., ...) = 4 + +0 setsockopt(4, SOL_SOCKET, SO_SNDBUF, [200000], 4) = 0 + + +0 write(4, ..., 30000) = 30000 + +0 > P. 1:10001(10000) ack 1 + +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }% + + +.11 < . 1:1(0) ack 4001 win 257 + +0 > P. 10001:18001(8000) ack 1 + + +.01 < . 1:1(0) ack 8001 win 257 + +0 > P. 18001:26001(8000) ack 1 + ++.005 < . 1:1(0) ack 10001 win 257 + +0 > P. 26001:30001(4000) ack 1 + + +0 %{ assert tcpi_snd_cwnd == 20, tcpi_snd_cwnd }% diff --git a/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-after-idle.pkt b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-after-idle.pkt new file mode 100644 index 000000000000..11b213be1138 --- /dev/null +++ b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-after-idle.pkt @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0 +// Test of slow start after idle +// This test expects tso size to be at least initial cwnd * mss + +`./defaults.sh +./set_sysctls.py /proc/sys/net/ipv4/tcp_slow_start_after_idle=1 \ + /proc/sys/net/ipv4/tcp_min_tso_segs=10` + + 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 + +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 + +0 bind(3, ..., ...) = 0 + +0 listen(3, 1) = 0 + + +0 < S 0:0(0) win 65535 + +0 > S. 0:0(0) ack 1 + +.1 < . 1:1(0) ack 1 win 511 + +0 accept(3, ..., ...) = 4 + +0 setsockopt(4, SOL_SOCKET, SO_SNDBUF, [200000], 4) = 0 + + +0 write(4, ..., 26000) = 26000 + +0 > P. 1:5001(5000) ack 1 + +0 > P. 5001:10001(5000) ack 1 + +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }% + + +.1 < . 1:1(0) ack 10001 win 511 + +0 %{ assert tcpi_snd_cwnd == 20, tcpi_snd_cwnd }% + +0 > P. 10001:20001(10000) ack 1 + +0 > P. 20001:26001(6000) ack 1 + + +.1 < . 1:1(0) ack 26001 win 511 + +0 %{ assert tcpi_snd_cwnd == 36, tcpi_snd_cwnd }% + + +2 write(4, ..., 20000) = 20000 +// If slow start after idle works properly, we should send 5 MSS here (cwnd/2) + +0 > P. 26001:31001(5000) ack 1 + +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }% + +// Reset sysctls +`/tmp/sysctl_restore_${PPID}.sh` diff --git a/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-after-win-update.pkt b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-after-win-update.pkt new file mode 100644 index 000000000000..577ed8c8852c --- /dev/null +++ b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-after-win-update.pkt @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0 +// Test of slow start after window update +// This test expects tso size to be at least initial cwnd * mss + +`./defaults.sh +./set_sysctls.py /proc/sys/net/ipv4/tcp_slow_start_after_idle=1 \ + /proc/sys/net/ipv4/tcp_min_tso_segs=10` + + 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 + +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 + +0 bind(3, ..., ...) = 0 + +0 listen(3, 1) = 0 + + +0 < S 0:0(0) win 65535 + +0 > S. 0:0(0) ack 1 + +.1 < . 1:1(0) ack 1 win 511 + +0 accept(3, ..., ...) = 4 + +0 setsockopt(4, SOL_SOCKET, SO_SNDBUF, [200000], 4) = 0 + + +0 write(4, ..., 26000) = 26000 + +0 > P. 1:5001(5000) ack 1 + +0 > P. 5001:10001(5000) ack 1 + +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }% + + +.1 < . 1:1(0) ack 10001 win 511 + +0 %{ assert tcpi_snd_cwnd == 20, tcpi_snd_cwnd }% + +0 > P. 10001:20001(10000) ack 1 + +0 > P. 20001:26001(6000) ack 1 + + +.1 < . 1:1(0) ack 26001 win 0 + +0 %{ assert tcpi_snd_cwnd == 36, tcpi_snd_cwnd }% + + +0 write(4, ..., 20000) = 20000 +// 1st win0 probe ++.3~+.310 > . 26000:26000(0) ack 1 + +0 %{ assert tcpi_snd_cwnd == 36, tcpi_snd_cwnd }% + +// 2nd win0 probe ++.6~+.620 > . 26000:26000(0) ack 1 + +0 %{ assert tcpi_snd_cwnd == 36, tcpi_snd_cwnd }% + +// 3rd win0 probe ++1.2~+1.240 > . 26000:26000(0) ack 1 + +0 %{ assert tcpi_snd_cwnd == 36, tcpi_snd_cwnd }% + + +.9 < . 1:1(0) ack 26001 win 511 + +0 > P. 26001:31001(5000) ack 1 + +// Reset sysctls +`/tmp/sysctl_restore_${PPID}.sh` diff --git a/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-app-limited-9-packets-out.pkt b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-app-limited-9-packets-out.pkt new file mode 100644 index 000000000000..869f32c35a2a --- /dev/null +++ b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-app-limited-9-packets-out.pkt @@ -0,0 +1,38 @@ +// SPDX-License-Identifier: GPL-2.0 +// Test of slow start when application-limited: in this case, +// with IW10, if we don't fully use our cwnd but instead +// send just 9 packets, then cwnd should grow to twice that +// value, or 18 packets. + +// Set up config. +`./defaults.sh` + + 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 + +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 + +0 bind(3, ..., ...) = 0 + +0 listen(3, 1) = 0 + + +.1 < S 0:0(0) win 32792 + +0 > S. 0:0(0) ack 1 + +.1 < . 1:1(0) ack 1 win 257 + +0 accept(3, ..., ...) = 4 + +0 setsockopt(4, SOL_SOCKET, SO_SNDBUF, [200000], 4) = 0 + + +0 write(4, ..., 9000) = 9000 + +0 > P. 1:9001(9000) ack 1 + +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }% + ++.105 < . 1:1(0) ack 2001 win 257 + +0 %{ assert tcpi_snd_cwnd == 12, tcpi_snd_cwnd }% + ++.005 < . 1:1(0) ack 4001 win 257 + +0 %{ assert tcpi_snd_cwnd == 14, tcpi_snd_cwnd }% + ++.005 < . 1:1(0) ack 6001 win 257 + +0 %{ assert tcpi_snd_cwnd == 16, tcpi_snd_cwnd }% + ++.005 < . 1:1(0) ack 8001 win 257 + +0 %{ assert tcpi_snd_cwnd == 18, tcpi_snd_cwnd }% + ++.005 < . 1:1(0) ack 9001 win 257 + +0 %{ assert tcpi_snd_cwnd == 18, tcpi_snd_cwnd }% diff --git a/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-app-limited.pkt b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-app-limited.pkt new file mode 100644 index 000000000000..0f77b7955db6 --- /dev/null +++ b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-app-limited.pkt @@ -0,0 +1,36 @@ +// SPDX-License-Identifier: GPL-2.0 +// Test of slow start when application-limited: in this case, +// with IW10, if we send exactly 10 packets then cwnd should grow to 20. + +// Set up config. +`./defaults.sh` + + 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 + +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 + +0 bind(3, ..., ...) = 0 + +0 listen(3, 1) = 0 + + +.1 < S 0:0(0) win 32792 + +0 > S. 0:0(0) ack 1 + +.1 < . 1:1(0) ack 1 win 257 + +0 accept(3, ..., ...) = 4 + +0 setsockopt(4, SOL_SOCKET, SO_SNDBUF, [200000], 4) = 0 + + +0 write(4, ..., 10000) = 10000 + +0 > P. 1:10001(10000) ack 1 + +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }% + ++.105 < . 1:1(0) ack 2001 win 257 + +0 %{ assert tcpi_snd_cwnd == 12, tcpi_snd_cwnd }% + ++.005 < . 1:1(0) ack 4001 win 257 + +0 %{ assert tcpi_snd_cwnd == 14, tcpi_snd_cwnd }% + ++.005 < . 1:1(0) ack 6001 win 257 + +0 %{ assert tcpi_snd_cwnd == 16, tcpi_snd_cwnd }% + ++.005 < . 1:1(0) ack 8001 win 257 + +0 %{ assert tcpi_snd_cwnd == 18, tcpi_snd_cwnd }% + ++.005 < . 1:1(0) ack 10001 win 257 + +0 %{ assert tcpi_snd_cwnd == 20, tcpi_snd_cwnd }% diff --git a/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-fq-ack-per-2pkt.pkt b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-fq-ack-per-2pkt.pkt new file mode 100644 index 000000000000..7e9c83d617c2 --- /dev/null +++ b/tools/testing/selftests/net/packetdrill/tcp_slow_start_slow-start-fq-ack-per-2pkt.pkt @@ -0,0 +1,63 @@ +// SPDX-License-Identifier: GPL-2.0 +// Test of slow start when not application-limited, so that +// the cwnd continues to grow, even if TSQ triggers. +// In this variant, the receiver ACKs every other packet, +// approximating standard delayed ACKs. + +// Note we use FQ/pacing to check if TCP Small Queues is not hurting + +`./defaults.sh +tc qdisc replace dev tun0 root fq +sysctl -q net/ipv4/tcp_pacing_ss_ratio=200 +sysctl -e -q net.ipv4.tcp_min_tso_segs=2` + + 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 + +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 + +0 bind(3, ..., ...) = 0 + +0 listen(3, 1) = 0 + + +.1 < S 0:0(0) win 32792 + +0 > S. 0:0(0) ack 1 + +.1 < . 1:1(0) ack 1 win 500 + +0 accept(3, ..., ...) = 4 + +0 setsockopt(4, SOL_SOCKET, SO_SNDBUF, [200000], 4) = 0 + + +0 write(4, ..., 40000) = 40000 +// This might change if we cook the initial packet with 10 MSS. + +0 > P. 1:2921(2920) ack 1 + +0 > P. 2921:5841(2920) ack 1 + +0 > P. 5841:8761(2920) ack 1 + +0 > P. 8761:11681(2920) ack 1 + +0 > P. 11681:14601(2920) ack 1 + +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }% + ++.105 < . 1:1(0) ack 2921 win 500 + +0 %{ assert tcpi_snd_cwnd == 12, tcpi_snd_cwnd }% + +// Note: after this commit : "net_sched: sch_fq: account for schedule/timers drifts" +// FQ notices that this packet missed the 'time to send next packet' computed +// when prior packet (11681:14601(2920)) was sent. +// So FQ will allow following packet to be sent a bit earlier (quantum/2) +// (FQ commit allows an application/cwnd limited flow to get at most quantum/2 extra credit) + +0 > P. 14601:17521(2920) ack 1 + ++.003 < . 1:1(0) ack 5841 win 500 + +0 %{ assert tcpi_snd_cwnd == 14, tcpi_snd_cwnd }% + ++.001 > P. 17521:20441(2920) ack 1 + ++.001 < . 1:1(0) ack 8761 win 500 + +0 %{ assert tcpi_snd_cwnd == 16, tcpi_snd_cwnd }% + +// remaining packets are delivered at a constant rate. ++.007 > P. 20441:23361(2920) ack 1 + ++.002 < . 1:1(0) ack 11681 win 500 + +0 %{ assert tcpi_snd_cwnd == 18, tcpi_snd_cwnd }% ++.001 < . 1:1(0) ack 14601 win 500 + ++.004 > P. 23361:26281(2920) ack 1 + ++.007 > P. 26281:29201(2920) ack 1 + + +0 %{ assert tcpi_snd_cwnd == 20, 'cwnd=%d' % tcpi_snd_cwnd }%