[PATCH 16/16] selftests: timers: nsleep-lat: Check all calls to clock_nanosleep() and clock_gettime()

From: Thomas Weißschuh (Schneider Electric)

Date: Thu Jul 30 2026 - 03:03:59 EST


Both these functions can fail.

The first calls to those functions are already checked and result in
KSFT_SKIP.

If they start failing afterwards unexpectedly, report a hard error.

Signed-off-by: Thomas Weißschuh (Schneider Electric) <thomas.weissschuh@xxxxxxxxxxxxx>
---
tools/testing/selftests/timers/nsleep-lat.c | 23 ++++++++++++++++-------
1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/timers/nsleep-lat.c b/tools/testing/selftests/timers/nsleep-lat.c
index 86af6d81cb14..fceb74c01d69 100644
--- a/tools/testing/selftests/timers/nsleep-lat.c
+++ b/tools/testing/selftests/timers/nsleep-lat.c
@@ -65,10 +65,16 @@ int nanosleep_lat_test(int clockid, long long ns)
count = 10;

/* First check relative latency */
- clock_gettime(clockid, &start);
- for (i = 0; i < count; i++)
- clock_nanosleep(clockid, 0, &target, NULL);
- clock_gettime(clockid, &end);
+ if (clock_gettime(clockid, &start))
+ return KSFT_FAIL;
+
+ for (i = 0; i < count; i++) {
+ if (clock_nanosleep(clockid, 0, &target, NULL))
+ return KSFT_FAIL;
+ }
+
+ if (clock_gettime(clockid, &end))
+ return KSFT_FAIL;

if (((timespec_sub(start, end)/count)-ns) > UNRESONABLE_LATENCY) {
ksft_print_msg("Large rel latency: %lld ns :", (timespec_sub(start, end)/count)-ns);
@@ -77,10 +83,13 @@ int nanosleep_lat_test(int clockid, long long ns)

/* Next check absolute latency */
for (i = 0; i < count; i++) {
- clock_gettime(clockid, &start);
+ if (clock_gettime(clockid, &start))
+ return KSFT_FAIL;
target = timespec_add(start, ns);
- clock_nanosleep(clockid, TIMER_ABSTIME, &target, NULL);
- clock_gettime(clockid, &end);
+ if (clock_nanosleep(clockid, TIMER_ABSTIME, &target, NULL))
+ return KSFT_FAIL;
+ if (clock_gettime(clockid, &end))
+ return KSFT_FAIL;
latency += timespec_sub(target, end);
}


--
2.55.0