kselftests: timers: set-timer-lat: Add one-shot timer test cases

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@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Stephen Boyd <stephen.boyd@linaro.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>

diff --git a/tools/testing/selftests/timers/set-timer-lat.c b/tools/testing/selftests/timers/set-timer-lat.c
index 10c2e18737c030b8ba0da69aeda018715069a2bb..15434da23b04686f17e61cf31f54f28fa2c0ffda 100644 (file)
--- 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();