[PATCH 4/6] kselftests: timers: set-timer-lat: Add one-shot timer test cases

From: John Stultz
Date: Fri Aug 18 2017 - 14:51:25 EST


From: Greg Hackmann <ghackmann@xxxxxxxxxx>

These testcases are motivated by a recent alarmtimer regression, which
caused one-shot CLOCK_{BOOTTIME,REALTIME}_ALARM timers to become
periodic timers.

The new testcases are very similar to the existing testcases for
repeating timers. But rather than waiting for 5 alarms, they wait for 5
seconds and verify that the alarm fired exactly once.

Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Miroslav Lichvar <mlichvar@xxxxxxxxxx>
Cc: Richard Cochran <richardcochran@xxxxxxxxx>
Cc: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: Stephen Boyd <stephen.boyd@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: linux-kselftest@xxxxxxxxxxxxxxx
Signed-off-by: Greg Hackmann <ghackmann@xxxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
---
tools/testing/selftests/timers/set-timer-lat.c | 86 ++++++++++++++++++++++----
1 file changed, 73 insertions(+), 13 deletions(-)

diff --git a/tools/testing/selftests/timers/set-timer-lat.c b/tools/testing/selftests/timers/set-timer-lat.c
index 10c2e18..15434da 100644
--- a/tools/testing/selftests/timers/set-timer-lat.c
+++ b/tools/testing/selftests/timers/set-timer-lat.c
@@ -20,6 +20,7 @@
*/


+#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <time.h>
@@ -122,17 +123,17 @@ void sigalarm(int signo)
max_latency_ns = delta_ns;
}

-void describe_timer(int flags)
+void describe_timer(int flags, int interval)
{
- printf("%-22s %s ",
+ printf("%-22s %s %s ",
clockstring(clock_id),
- flags ? "ABSTIME":"RELTIME");
+ flags ? "ABSTIME":"RELTIME",
+ interval ? "PERIODIC":"ONE-SHOT");
}

-int do_timer(int clock_id, int flags)
+int setup_timer(int clock_id, int flags, int interval, timer_t *tm1)
{
struct sigevent se;
- timer_t tm1;
struct itimerspec its1, its2;
int err;

@@ -146,7 +147,7 @@ int do_timer(int clock_id, int flags)
alarmcount = 0;
timer_fired_early = 0;

- err = timer_create(clock_id, &se, &tm1);
+ err = timer_create(clock_id, &se, tm1);
if (err) {
if ((clock_id == CLOCK_REALTIME_ALARM) ||
(clock_id == CLOCK_BOOTTIME_ALARM)) {
@@ -167,19 +168,23 @@ int do_timer(int clock_id, int flags)
its1.it_value.tv_sec = TIMER_SECS;
its1.it_value.tv_nsec = 0;
}
- its1.it_interval.tv_sec = TIMER_SECS;
+ its1.it_interval.tv_sec = interval;
its1.it_interval.tv_nsec = 0;

- err = timer_settime(tm1, flags, &its1, &its2);
+ err = timer_settime(*tm1, flags, &its1, &its2);
if (err) {
printf("%s - timer_settime() failed\n", clockstring(clock_id));
return -1;
}

- while (alarmcount < 5)
- sleep(1);
+ return 0;
+}

- describe_timer(flags);
+int check_timer_latency(int flags, int interval)
+{
+ int err = 0;
+
+ describe_timer(flags, interval);
printf("timer fired early: %7d : ", timer_fired_early);
if (!timer_fired_early) {
printf("[OK]\n");
@@ -188,10 +193,9 @@ int do_timer(int clock_id, int flags)
err = -1;
}

- describe_timer(flags);
+ describe_timer(flags, interval);
printf("max latency: %10lld ns : ", max_latency_ns);

- timer_delete(tm1);
if (max_latency_ns < UNRESONABLE_LATENCY) {
printf("[OK]\n");
} else {
@@ -201,6 +205,60 @@ int do_timer(int clock_id, int flags)
return err;
}

+int check_alarmcount(int flags, int interval)
+{
+ describe_timer(flags, interval);
+ printf("count: %19d : ", alarmcount);
+ if (alarmcount == 1) {
+ printf("[OK]\n");
+ return 0;
+ }
+ printf("[FAILED]\n");
+ return -1;
+}
+
+int do_timer(int clock_id, int flags)
+{
+ timer_t tm1;
+ const int interval = TIMER_SECS;
+ int err;
+
+ err = setup_timer(clock_id, flags, interval, &tm1);
+ if (err)
+ return err;
+
+ while (alarmcount < 5)
+ sleep(1);
+
+ timer_delete(tm1);
+ return check_timer_latency(flags, interval);
+}
+
+int do_timer_oneshot(int clock_id, int flags)
+{
+ timer_t tm1;
+ const int interval = 0;
+ struct timeval timeout;
+ fd_set fds;
+ int err;
+
+ err = setup_timer(clock_id, flags, interval, &tm1);
+ if (err)
+ return err;
+
+ memset(&timeout, 0, sizeof(timeout));
+ timeout.tv_sec = 5;
+ FD_ZERO(&fds);
+ do {
+ err = select(FD_SETSIZE, &fds, NULL, NULL, &timeout);
+ } while (err == -1 && errno == EINTR);
+
+ timer_delete(tm1);
+ err = check_timer_latency(flags, interval);
+ err |= check_alarmcount(flags, interval);
+ return err;
+}
+
int main(void)
{
struct sigaction act;
@@ -226,6 +284,8 @@ int main(void)

ret |= do_timer(clock_id, TIMER_ABSTIME);
ret |= do_timer(clock_id, 0);
+ ret |= do_timer_oneshot(clock_id, TIMER_ABSTIME);
+ ret |= do_timer_oneshot(clock_id, 0);
}
if (ret)
return ksft_exit_fail();
--
2.7.4