selftests: drv-net: in so_txtime tell apart sw from hw pacing

Detect software pacing in so_txtime.c using SO_TIMESTAMPING.

If '-H' (hw) is passed

1. measure sw tx delay with SOF_TIMESTAMPING_TX_SOFTWARE, and
2. fail if delay exceeds a threshold, indicating pacing

This will be used in the next patch in the series.

Also extend while condition to account for possible variance.
This applies to all tests, not just the new '-H' variants.

Also reorder getopt parameters to make them alphabetical.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260910171131.2532487-7-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 79 insertions, 16 deletions

diff --git a/tools/testing/selftests/drivers/net/so_txtime.c b/tools/testing/selftests/drivers/net/so_txtime.c
index f6f3253ed174..9ebe9f91227c 100644
--- a/tools/testing/selftests/drivers/net/so_txtime.c
+++ b/tools/testing/selftests/drivers/net/so_txtime.c
@@ -42,8 +42,10 @@ static bool	cfg_machine_slow;
 static uint64_t	cfg_start_time_ns;
 static int	cfg_mark;
 static bool	cfg_rx;
+static bool	cfg_verify_hw_offload;
 
 static uint64_t glob_tstart;
+static uint64_t glob_tstart_real;
 static uint64_t tdeliver_max;
 
 static int errors;
@@ -191,12 +193,32 @@ static int do_recv_errqueue_txtime(struct sock_extended_err *err,
 	return 1;
 }
 
-static int do_recv_errqueue(int fdt)
+static int do_recv_errqueue_timestamping(struct scm_timestamping *tss)
+{
+	int64_t ts;
+
+	ts = tss->ts[0].tv_sec * 1000ULL * 1000 * 1000;
+	ts += tss->ts[0].tv_nsec;
+	ts -= glob_tstart_real;
+	ts /= 1000;
+
+	if (ts > cfg_variance_us) {
+		fprintf(stderr, "sw delay %" PRId64 "us exceeds bounds\n", ts);
+		if (!cfg_machine_slow)
+			errors++;
+	}
+
+	return 1;
+}
+
+static int do_recv_errqueue(int fdt, int *num_ts)
 {
 	char control[CMSG_SPACE(sizeof(struct sock_extended_err)) +
+		     CMSG_SPACE(sizeof(struct scm_timestamping)) +
 		     CMSG_SPACE(sizeof(struct sockaddr_in6))] = {0};
 	char data[sizeof(struct ethhdr) + sizeof(struct ipv6hdr) +
 		  sizeof(struct udphdr) + 1];
+	struct scm_timestamping *tss;
 	struct sock_extended_err *err;
 	int ret, num_tstamp = 0;
 	struct msghdr msg = {0};
@@ -222,16 +244,29 @@ static int do_recv_errqueue(int fdt)
 			error(1, 0, "errqueue: flags 0x%x\n", msg.msg_flags);
 
 		cm = CMSG_FIRSTHDR(&msg);
+		tss = NULL;
+
+		if (cm->cmsg_level == SOL_SOCKET &&
+		    cm->cmsg_type == SCM_TIMESTAMPING) {
+			tss = (void *)CMSG_DATA(cm);
+			cm = CMSG_NXTHDR(&msg, cm);
+			if (!cm)
+				error(1, 0, "timestamp missing ip err\n");
+		}
+
 		if (cm->cmsg_level != cfg_errq_level ||
 		    cm->cmsg_type != cfg_errq_type)
 			error(1, 0, "errqueue: type 0x%x.0x%x\n",
 				    cm->cmsg_level, cm->cmsg_type);
 
 		err = (struct sock_extended_err *)CMSG_DATA(cm);
-		if (err->ee_origin != SO_EE_ORIGIN_TXTIME)
+		if (err->ee_origin == SO_EE_ORIGIN_TXTIME)
+			num_tstamp += do_recv_errqueue_txtime(err, data[ret - 1]);
+		else if (err->ee_origin == SO_EE_ORIGIN_TIMESTAMPING && tss)
+			*num_ts += do_recv_errqueue_timestamping(tss);
+		else
 			error(1, 0, "errqueue: origin 0x%x\n", err->ee_origin);
 
-		num_tstamp += do_recv_errqueue_txtime(err, data[ret - 1]);
 		msg.msg_flags = 0;
 		msg.msg_controllen = sizeof(control);
 	}
@@ -243,7 +278,7 @@ static void recv_errqueue_msgs(int fdt)
 {
 	struct pollfd pfd = { .fd = fdt, .events = POLLERR };
 	const int timeout_ms = 10;
-	int ret, num_tstamp = 0;
+	int ret, num_tstamp = 0, num_ts = 0;
 
 	do {
 		ret = poll(&pfd, 1, timeout_ms);
@@ -251,12 +286,20 @@ static void recv_errqueue_msgs(int fdt)
 			error(1, errno, "poll");
 
 		if (ret && (pfd.revents & POLLERR))
-			num_tstamp += do_recv_errqueue(fdt);
+			num_tstamp += do_recv_errqueue(fdt, &num_ts);
 
-		if (num_tstamp == cfg_num_pkt)
+		if (num_tstamp == cfg_num_pkt || num_ts == cfg_num_pkt)
 			break;
 
-	} while (gettime_ns(cfg_clockid) < tdeliver_max);
+	} while (gettime_ns(cfg_clockid) <
+		 tdeliver_max + (cfg_variance_us * 1000));
+
+	if (cfg_verify_hw_offload && num_ts != cfg_num_pkt) {
+		fprintf(stderr, "missing timestamps: expected %d, got %d\n",
+			cfg_num_pkt, num_ts);
+		if (!cfg_machine_slow)
+			errors++;
+	}
 }
 
 static void start_time_wait(void)
@@ -301,6 +344,17 @@ static void setsockopt_txtime(int fd)
 		error(1, 0, "getsockopt txtime: mismatch");
 }
 
+static void setsockopt_txtimestamping(int fd)
+{
+	int val = SOF_TIMESTAMPING_TX_SOFTWARE |
+		  SOF_TIMESTAMPING_SOFTWARE |
+		  SOF_TIMESTAMPING_OPT_TSONLY;
+
+	if (setsockopt(fd, SOL_SOCKET, SO_TIMESTAMPING,
+		       &val, sizeof(val)))
+		error(1, errno, "setsockopt timestamping");
+}
+
 static int setup_tx(struct sockaddr *addr, socklen_t alen)
 {
 	int fd;
@@ -314,6 +368,9 @@ static int setup_tx(struct sockaddr *addr, socklen_t alen)
 
 	setsockopt_txtime(fd);
 
+	if (cfg_verify_hw_offload)
+		setsockopt_txtimestamping(fd);
+
 	if (cfg_mark &&
 	    setsockopt(fd, SOL_SOCKET, SO_MARK, &cfg_mark, sizeof(cfg_mark)))
 		error(1, errno, "setsockopt mark");
@@ -354,6 +411,8 @@ static void do_test_tx(struct sockaddr *addr, socklen_t alen)
 
 	start_time_wait();
 	glob_tstart = gettime_ns(cfg_clockid);
+	glob_tstart_real = gettime_ns(CLOCK_REALTIME);
+	tdeliver_max = glob_tstart;
 
 	for (i = 0; i < cfg_num_pkt; i++)
 		do_send_one(fdt, &cfg_buf[i]);
@@ -446,10 +505,11 @@ static void usage(const char *progname)
 			"  -6            only IPv6\n"
 			"  -c <clock>    monotonic or tai (default)\n"
 			"  -D <addr>     destination IP address (server)\n"
-			"  -S <addr>     source IP address (client)\n"
+			"  -H            verify hardware offload (tx)\n"
+			"  -m <mark>     socket mark\n"
 			"  -r            run rx mode\n"
+			"  -S <addr>     source IP address (client)\n"
 			"  -t <nsec>     start time (UTC nanoseconds)\n"
-			"  -m <mark>     socket mark\n"
 			"\n",
 			progname);
 	exit(1);
@@ -461,7 +521,7 @@ static void parse_opts(int argc, char **argv)
 	int domain = PF_UNSPEC;
 	int c;
 
-	while ((c = getopt(argc, argv, "46c:S:D:rt:m:")) != -1) {
+	while ((c = getopt(argc, argv, "46c:D:Hm:rS:t:")) != -1) {
 		switch (c) {
 		case '4':
 			if (domain != PF_UNSPEC)
@@ -488,21 +548,24 @@ static void parse_opts(int argc, char **argv)
 			else
 				error(1, 0, "unknown clock id %s", optarg);
 			break;
-		case 'S':
-			saddr = optarg;
-			break;
 		case 'D':
 			daddr = optarg;
 			break;
+		case 'H':
+			cfg_verify_hw_offload = true;
+			break;
+		case 'm':
+			cfg_mark = strtol(optarg, NULL, 0);
+			break;
 		case 'r':
 			cfg_rx = true;
 			break;
+		case 'S':
+			saddr = optarg;
+			break;
 		case 't':
 			cfg_start_time_ns = strtoll(optarg, NULL, 0);
 			break;
-		case 'm':
-			cfg_mark = strtol(optarg, NULL, 0);
-			break;
 		default:
 			usage(argv[0]);
 		}