[PATCH net-next v3] selftests/net: convert so_txtime to drv-net

[PATCH net-next v3] selftests/net: convert so_txtime to drv-net

[Willem de Bruijn]

From: Willem de Bruijn <willemb@google.com>

In preparation for extending to pacing hardware offload, convert the
so_txtime.sh test to a drv-net test that can be run against netdevsim
and real hardware.

Also update so_txtime.c to not exit on first failure, but run to
completion and report exit code there. This helps with debugging
unexpected results, especially when processing multiple packets,
as in the "reverse_order" testcase.

Signed-off-by: Willem de Bruijn <willemb@google.com>

----

v2 -> v3

- Makefile: move so_txtime from YNL_GEN_FILES to TEST_GEN_FILES

v2: https://lore.kernel.org/netdev/20260405014458.1038165-1-willemdebruijn.kernel@gmail.com/

v1 -> v2
- move so_txtime.c for net/lib to drivers/net (Jakub)
- fix drivers/net/config order (Jakub)
- detect passing when failure is expected (Jakub, Sashiko)
- pass pylint --disable=R (Jakub)
- only call ksft_run once (Jakub)
- do not sleep if waiting time is negative (Sashiko)
- add \n when converting error() to fprintf() (Sashiko)
- 4 space indentation, instead of 2 space
- increase sync delay from 100 to 200ms, to fix rare vng flakes

v1: https://lore.kernel.org/netdev/20260403175047.152646-1-willemdebruijn.kernel@gmail.com/
---
 .../testing/selftests/drivers/net/.gitignore  |   1 +
 tools/testing/selftests/drivers/net/Makefile  |   2 +
 tools/testing/selftests/drivers/net/config    |   2 +
 .../selftests/{ => drivers}/net/so_txtime.c   |  24 +++-
 .../selftests/drivers/net/so_txtime.py        |  88 ++++++++++++++
 tools/testing/selftests/net/.gitignore        |   1 -
 tools/testing/selftests/net/Makefile          |   2 -
 tools/testing/selftests/net/so_txtime.sh      | 110 ------------------
 8 files changed, 112 insertions(+), 118 deletions(-)
 rename tools/testing/selftests/{ => drivers}/net/so_txtime.c (96%)
 create mode 100755 tools/testing/selftests/drivers/net/so_txtime.py
 delete mode 100755 tools/testing/selftests/net/so_txtime.sh

diff --git a/tools/testing/selftests/drivers/net/.gitignore b/tools/testing/selftests/drivers/net/.gitignore
index 585ecb4d5dc4..e5314ce4bb2d 100644
--- a/tools/testing/selftests/drivers/net/.gitignore
+++ b/tools/testing/selftests/drivers/net/.gitignore
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 napi_id_helper
 psp_responder
+so_txtime
diff --git a/tools/testing/selftests/drivers/net/Makefile b/tools/testing/selftests/drivers/net/Makefile
index 7c7fa75b80c2..49a61b506f53 100644
--- a/tools/testing/selftests/drivers/net/Makefile
+++ b/tools/testing/selftests/drivers/net/Makefile
@@ -7,6 +7,7 @@ TEST_INCLUDES := $(wildcard lib/py/*.py) \
 
 TEST_GEN_FILES := \
 	napi_id_helper \
+	so_txtime \
 # end of TEST_GEN_FILES
 
 TEST_PROGS := \
@@ -20,6 +21,7 @@ TEST_PROGS := \
 	queues.py \
 	ring_reconfig.py \
 	shaper.py \
+	so_txtime.py \
 	stats.py \
 	xdp.py \
 # end of TEST_PROGS
diff --git a/tools/testing/selftests/drivers/net/config b/tools/testing/selftests/drivers/net/config
index 77ccf83d87e0..2d39f263e03b 100644
--- a/tools/testing/selftests/drivers/net/config
+++ b/tools/testing/selftests/drivers/net/config
@@ -7,4 +7,6 @@ CONFIG_NETCONSOLE=m
 CONFIG_NETCONSOLE_DYNAMIC=y
 CONFIG_NETCONSOLE_EXTENDED_LOG=y
 CONFIG_NETDEVSIM=m
+CONFIG_NET_SCH_ETF=m
+CONFIG_NET_SCH_FQ=m
 CONFIG_XDP_SOCKETS=y
diff --git a/tools/testing/selftests/net/so_txtime.c b/tools/testing/selftests/drivers/net/so_txtime.c
similarity index 96%
rename from tools/testing/selftests/net/so_txtime.c
rename to tools/testing/selftests/drivers/net/so_txtime.c
index b76df1efc2ef..7d144001ecf2 100644
--- a/tools/testing/selftests/net/so_txtime.c
+++ b/tools/testing/selftests/drivers/net/so_txtime.c
@@ -33,6 +33,8 @@
 #include <unistd.h>
 #include <poll.h>
 
+#include "kselftest.h"
+
 static int	cfg_clockid	= CLOCK_TAI;
 static uint16_t	cfg_port	= 8000;
 static int	cfg_variance_us	= 4000;
@@ -43,6 +45,8 @@ static bool	cfg_rx;
 static uint64_t glob_tstart;
 static uint64_t tdeliver_max;
 
+static int errors;
+
 /* encode one timed transmission (of a 1B payload) */
 struct timed_send {
 	char	data;
@@ -131,13 +135,15 @@ static void do_recv_one(int fdr, struct timed_send *ts)
 	fprintf(stderr, "payload:%c delay:%lld expected:%lld (us)\n",
 			rbuf[0], (long long)tstop, (long long)texpect);
 
-	if (rbuf[0] != ts->data)
-		error(1, 0, "payload mismatch. expected %c", ts->data);
+	if (rbuf[0] != ts->data) {
+		fprintf(stderr, "payload mismatch. expected %c\n", ts->data);
+		errors++;
+	}
 
 	if (llabs(tstop - texpect) > cfg_variance_us) {
 		fprintf(stderr, "exceeds variance (%d us)\n", cfg_variance_us);
 		if (!getenv("KSFT_MACHINE_SLOW"))
-			exit(1);
+			errors++;
 	}
 }
 
@@ -255,8 +261,11 @@ static void start_time_wait(void)
 		return;
 
 	now = gettime_ns(CLOCK_REALTIME);
-	if (cfg_start_time_ns < now)
+	if (cfg_start_time_ns < now) {
+		fprintf(stderr, "FAIL: start time already passed\n");
+		errors++;
 		return;
+	}
 
 	err = usleep((cfg_start_time_ns - now) / 1000);
 	if (err)
@@ -513,5 +522,10 @@ int main(int argc, char **argv)
 	else
 		do_test_tx((void *)&cfg_src_addr, cfg_alen);
 
-	return 0;
+	if (errors) {
+		fprintf(stderr, "FAIL: %d errors\n", errors);
+		return KSFT_FAIL;
+	}
+
+	return KSFT_PASS;
 }
diff --git a/tools/testing/selftests/drivers/net/so_txtime.py b/tools/testing/selftests/drivers/net/so_txtime.py
new file mode 100755
index 000000000000..31b95a7b5b8b
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/so_txtime.py
@@ -0,0 +1,88 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+"""Regression tests for the SO_TXTIME interface.
+
+Test delivery time in FQ and ETF qdiscs.
+"""
+
+import time
+
+from lib.py import ksft_exit, ksft_run, ksft_variants
+from lib.py import KsftNamedVariant, KsftSkipEx
+from lib.py import NetDrvEpEnv, bkg, cmd
+
+
+def test_so_txtime(cfg, clockid, ipver, args_tx, args_rx, expect_fail):
+    """Main function. Run so_txtime as sender and receiver."""
+    bin_path = cfg.test_dir / "so_txtime"
+
+    tstart = time.time_ns() + 200_000_000
+
+    cmd_addr = f"-S {cfg.addr_v[ipver]} -D {cfg.remote_addr_v[ipver]}"
+    cmd_base = f"{bin_path} -{ipver} -c {clockid} -t {tstart} {cmd_addr}"
+    cmd_rx = f"{cmd_base} {args_rx} -r"
+    cmd_tx = f"{cmd_base} {args_tx}"
+
+    with bkg(cmd_rx, host=cfg.remote, fail=(not expect_fail), exit_wait=True):
+        cmd(cmd_tx)
+
+
+def _test_variants_mono():
+    for ipver in ["4", "6"]:
+        for testcase in [
+            ["no_delay", "a,-1", "a,-1"],
+            ["zero_delay", "a,0", "a,0"],
+            ["one_pkt", "a,10", "a,10"],
+            ["in_order", "a,10,b,20", "a,10,b,20"],
+            ["reverse_order", "a,20,b,10", "b,20,a,20"],
+        ]:
+            name = f"_v{ipver}_{testcase[0]}"
+            yield KsftNamedVariant(name, ipver, testcase[1], testcase[2])
+
+
+@ksft_variants(_test_variants_mono())
+def test_so_txtime_mono(cfg, ipver, args_tx, args_rx):
+    """Run all variants of monotonic (fq) tests."""
+    cmd(f"tc qdisc replace dev {cfg.ifname} root fq")
+    test_so_txtime(cfg, "mono", ipver, args_tx, args_rx, False)
+
+
+def _test_variants_etf():
+    for ipver in ["4", "6"]:
+        for testcase in [
+            ["no_delay", "a,-1", "a,-1", True],
+            ["zero_delay", "a,0", "a,0", True],
+            ["one_pkt", "a,10", "a,10", False],
+            ["in_order", "a,10,b,20", "a,10,b,20", False],
+            ["reverse_order", "a,20,b,10", "b,10,a,20", False],
+        ]:
+            name = f"_v{ipver}_{testcase[0]}"
+            yield KsftNamedVariant(
+                name, ipver, testcase[1], testcase[2], testcase[3]
+            )
+
+
+@ksft_variants(_test_variants_etf())
+def test_so_txtime_etf(cfg, ipver, args_tx, args_rx, expect_fail):
+    """Run all variants of etf tests."""
+    try:
+        # ETF does not support change, so remove and re-add it instead.
+        cmd_prefix = f"tc qdisc replace dev {cfg.ifname} root"
+        cmd(f"{cmd_prefix} pfifo_fast")
+        cmd(f"{cmd_prefix} etf clockid CLOCK_TAI delta 400000")
+    except Exception as e:
+        raise KsftSkipEx("tc does not support qdisc etf. skipping") from e
+
+    test_so_txtime(cfg, "tai", ipver, args_tx, args_rx, expect_fail)
+
+
+def main() -> None:
+    """Boilerplate ksft main."""
+    with NetDrvEpEnv(__file__) as cfg:
+        ksft_run([test_so_txtime_mono, test_so_txtime_etf], args=(cfg,))
+    ksft_exit()
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore
index 97ad4d551d44..02ad4c99a2b4 100644
--- a/tools/testing/selftests/net/.gitignore
+++ b/tools/testing/selftests/net/.gitignore
@@ -40,7 +40,6 @@ skf_net_off
 socket
 so_incoming_cpu
 so_netns_cookie
-so_txtime
 so_rcv_listener
 stress_reuseport_listen
 tap
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 6bced3ed798b..b7f51e8f190f 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -81,7 +81,6 @@ TEST_PROGS := \
 	rxtimestamp.sh \
 	sctp_vrf.sh \
 	skf_net_off.sh \
-	so_txtime.sh \
 	srv6_end_dt46_l3vpn_test.sh \
 	srv6_end_dt4_l3vpn_test.sh \
 	srv6_end_dt6_l3vpn_test.sh \
@@ -154,7 +153,6 @@ TEST_GEN_FILES := \
 	skf_net_off \
 	so_netns_cookie \
 	so_rcv_listener \
-	so_txtime \
 	socket \
 	stress_reuseport_listen \
 	tcp_fastopen_backup_key \
diff --git a/tools/testing/selftests/net/so_txtime.sh b/tools/testing/selftests/net/so_txtime.sh
deleted file mode 100755
index 5e861ad32a42..000000000000
--- a/tools/testing/selftests/net/so_txtime.sh
+++ /dev/null
@@ -1,110 +0,0 @@
-#!/bin/bash
-# SPDX-License-Identifier: GPL-2.0
-#
-# Regression tests for the SO_TXTIME interface
-
-set -e
-
-readonly ksft_skip=4
-readonly DEV="veth0"
-readonly BIN="./so_txtime"
-
-readonly RAND="$(mktemp -u XXXXXX)"
-readonly NSPREFIX="ns-${RAND}"
-readonly NS1="${NSPREFIX}1"
-readonly NS2="${NSPREFIX}2"
-
-readonly SADDR4='192.168.1.1'
-readonly DADDR4='192.168.1.2'
-readonly SADDR6='fd::1'
-readonly DADDR6='fd::2'
-
-cleanup() {
-	ip netns del "${NS2}"
-	ip netns del "${NS1}"
-}
-
-trap cleanup EXIT
-
-# Create virtual ethernet pair between network namespaces
-ip netns add "${NS1}"
-ip netns add "${NS2}"
-
-ip link add "${DEV}" netns "${NS1}" type veth \
-  peer name "${DEV}" netns "${NS2}"
-
-# Bring the devices up
-ip -netns "${NS1}" link set "${DEV}" up
-ip -netns "${NS2}" link set "${DEV}" up
-
-# Set fixed MAC addresses on the devices
-ip -netns "${NS1}" link set dev "${DEV}" address 02:02:02:02:02:02
-ip -netns "${NS2}" link set dev "${DEV}" address 06:06:06:06:06:06
-
-# Add fixed IP addresses to the devices
-ip -netns "${NS1}" addr add 192.168.1.1/24 dev "${DEV}"
-ip -netns "${NS2}" addr add 192.168.1.2/24 dev "${DEV}"
-ip -netns "${NS1}" addr add       fd::1/64 dev "${DEV}" nodad
-ip -netns "${NS2}" addr add       fd::2/64 dev "${DEV}" nodad
-
-run_test() {
-	local readonly IP="$1"
-	local readonly CLOCK="$2"
-	local readonly TXARGS="$3"
-	local readonly RXARGS="$4"
-
-	if [[ "${IP}" == "4" ]]; then
-		local readonly SADDR="${SADDR4}"
-		local readonly DADDR="${DADDR4}"
-	elif [[ "${IP}" == "6" ]]; then
-		local readonly SADDR="${SADDR6}"
-		local readonly DADDR="${DADDR6}"
-	else
-		echo "Invalid IP version ${IP}"
-		exit 1
-	fi
-
-	local readonly START="$(date +%s%N --date="+ 0.1 seconds")"
-
-	ip netns exec "${NS2}" "${BIN}" -"${IP}" -c "${CLOCK}" -t "${START}" -S "${SADDR}" -D "${DADDR}" "${RXARGS}" -r &
-	ip netns exec "${NS1}" "${BIN}" -"${IP}" -c "${CLOCK}" -t "${START}" -S "${SADDR}" -D "${DADDR}" "${TXARGS}"
-	wait "$!"
-}
-
-do_test() {
-	run_test $@
-	[ $? -ne 0 ] && ret=1
-}
-
-do_fail_test() {
-	run_test $@
-	[ $? -eq 0 ] && ret=1
-}
-
-ip netns exec "${NS1}" tc qdisc add dev "${DEV}" root fq
-set +e
-ret=0
-do_test 4 mono a,-1 a,-1
-do_test 6 mono a,0 a,0
-do_test 6 mono a,10 a,10
-do_test 4 mono a,10,b,20 a,10,b,20
-do_test 6 mono a,20,b,10 b,20,a,20
-
-if ip netns exec "${NS1}" tc qdisc replace dev "${DEV}" root etf clockid CLOCK_TAI delta 400000; then
-	do_fail_test 4 tai a,-1 a,-1
-	do_fail_test 6 tai a,0 a,0
-	do_test 6 tai a,10 a,10
-	do_test 4 tai a,10,b,20 a,10,b,20
-	do_test 6 tai a,20,b,10 b,10,a,20
-else
-	echo "tc ($(tc -V)) does not support qdisc etf. skipping"
-	[ $ret -eq 0 ] && ret=$ksft_skip
-fi
-
-if [ $ret -eq 0 ]; then
-	echo OK. All tests passed
-elif [[ $ret -ne $ksft_skip && -n "$KSFT_MACHINE_SLOW" ]]; then
-	echo "Ignoring errors due to slow environment" 1>&2
-	ret=0
-fi
-exit $ret
-- 
2.53.0.1213.gd9a14994de-goog

Re: [PATCH net-next v3] selftests/net: convert so_txtime to drv-net

[Jakub Kicinski]

On Sun,  5 Apr 2026 22:49:22 -0400 Willem de Bruijn wrote:
> +@ksft_variants(_test_variants_mono())
> +def test_so_txtime_mono(cfg, ipver, args_tx, args_rx):
> +    """Run all variants of monotonic (fq) tests."""
> +    cmd(f"tc qdisc replace dev {cfg.ifname} root fq")
> +    test_so_txtime(cfg, "mono", ipver, args_tx, args_rx, False)
> +
> +
> +def _test_variants_etf():
> +    for ipver in ["4", "6"]:
> +        for testcase in [
> +            ["no_delay", "a,-1", "a,-1", True],
> +            ["zero_delay", "a,0", "a,0", True],
> +            ["one_pkt", "a,10", "a,10", False],
> +            ["in_order", "a,10,b,20", "a,10,b,20", False],
> +            ["reverse_order", "a,20,b,10", "b,10,a,20", False],
> +        ]:
> +            name = f"_v{ipver}_{testcase[0]}"

nit: looking at the results in NIPA:
https://netdev-ctrl.bots.linux.dev/logs/vmksft/net-drv/results/593442/5-so-txtime-py/stdout
the leading _ seems unnecessary? 

> +            yield KsftNamedVariant(
> +                name, ipver, testcase[1], testcase[2], testcase[3]
> +            )
> +
> +
> +@ksft_variants(_test_variants_etf())
> +def test_so_txtime_etf(cfg, ipver, args_tx, args_rx, expect_fail):
> +    """Run all variants of etf tests."""
> +    try:
> +        # ETF does not support change, so remove and re-add it instead.
> +        cmd_prefix = f"tc qdisc replace dev {cfg.ifname} root"
> +        cmd(f"{cmd_prefix} pfifo_fast")
> +        cmd(f"{cmd_prefix} etf clockid CLOCK_TAI delta 400000")
> +    except Exception as e:
> +        raise KsftSkipEx("tc does not support qdisc etf. skipping") from e
> +
> +    test_so_txtime(cfg, "tai", ipver, args_tx, args_rx, expect_fail)

I _think_ we'll leave ETF installed on the device after the test?
That seems not super great. As we discussed before rebuilding the 
whole hierarchy will be tedious but we could at least replace with
mq on exit and let it put whatever the default qdisc is as its leaves?