I'm sending some patches that were orignally in
https://lore.kernel.org/lkml/[email protected]/
to prevent the timer_distribution test from hanging and also fix some
format inconsistencies.
Edward Liaw (3):
selftests/timers/posix_timers: Make signal distribution test less
fragile
selftests/timers/posix_timers: Use TAP reporting format
selftests/timers/posix_timers: Use llabs for long long
tools/testing/selftests/timers/posix_timers.c | 196 ++++++++----------
1 file changed, 89 insertions(+), 107 deletions(-)
--
2.44.0.rc1.240.g4c46232300-goog
The signal distribution test has a tendency to hang for a long time as the
signal delivery is not really evenly distributed.
Increasing the timer interval to 10ms makes this less likely. Add a timeout
to catch the case where it hangs and terminate the test gracefully.
While at it get rid of the pointless atomic operation on a the thread local
variable in the signal handler.
Signed-off-by: Thomas Gleixner <[email protected]>
[edliaw: Rebase and fix checkpatch recommendations]
Signed-off-by: Edward Liaw <[email protected]>
---
tools/testing/selftests/timers/posix_timers.c | 43 ++++++++++++-------
1 file changed, 27 insertions(+), 16 deletions(-)
diff --git a/tools/testing/selftests/timers/posix_timers.c b/tools/testing/selftests/timers/posix_timers.c
index d49dd3ffd0d9..03779b6b3c20 100644
--- a/tools/testing/selftests/timers/posix_timers.c
+++ b/tools/testing/selftests/timers/posix_timers.c
@@ -24,7 +24,8 @@ static volatile int done;
/* Busy loop in userspace to elapse ITIMER_VIRTUAL */
static void user_loop(void)
{
- while (!done);
+ while (!done)
+ continue;
}
/*
@@ -184,18 +185,19 @@ static int check_timer_create(int which)
return 0;
}
-int remain;
-__thread int got_signal;
+static int remain;
+static __thread int got_signal;
static void *distribution_thread(void *arg)
{
- while (__atomic_load_n(&remain, __ATOMIC_RELAXED));
+ while (__atomic_load_n(&remain, __ATOMIC_RELAXED) && !done)
+ continue;
return NULL;
}
static void distribution_handler(int nr)
{
- if (!__atomic_exchange_n(&got_signal, 1, __ATOMIC_RELAXED))
+ if (++got_signal == 1)
__atomic_fetch_sub(&remain, 1, __ATOMIC_RELAXED);
}
@@ -205,17 +207,19 @@ static void distribution_handler(int nr)
*/
static int check_timer_distribution(void)
{
- int err, i;
- timer_t id;
const int nthreads = 10;
pthread_t threads[nthreads];
struct itimerspec val = {
.it_value.tv_sec = 0,
- .it_value.tv_nsec = 1000 * 1000,
+ .it_value.tv_nsec = 20 * 1000 * 1000,
.it_interval.tv_sec = 0,
- .it_interval.tv_nsec = 1000 * 1000,
+ .it_interval.tv_nsec = 20 * 1000 * 1000,
};
+ time_t start, now;
+ int err, i;
+ timer_t id;
+ done = 0;
remain = nthreads + 1; /* worker threads + this thread */
signal(SIGALRM, distribution_handler);
err = timer_create(CLOCK_PROCESS_CPUTIME_ID, NULL, &id);
@@ -240,7 +244,18 @@ static int check_timer_distribution(void)
}
/* Wait for all threads to receive the signal. */
- while (__atomic_load_n(&remain, __ATOMIC_RELAXED));
+ now = start = time(NULL);
+ while (__atomic_load_n(&remain, __ATOMIC_RELAXED)) {
+ now = time(NULL);
+ if (now - start > 5)
+ break;
+ }
+ done = 1;
+
+ if (timer_delete(id)) {
+ ksft_perror("Can't delete timer\n");
+ return -1;
+ }
for (i = 0; i < nthreads; i++) {
err = pthread_join(threads[i], NULL);
@@ -251,12 +266,8 @@ static int check_timer_distribution(void)
}
}
- if (timer_delete(id)) {
- ksft_perror("Can't delete timer");
- return -1;
- }
+ ksft_test_result((now - start <= 5), "%s\n", __func__);
- ksft_test_result_pass("check_timer_distribution\n");
return 0;
}
@@ -265,7 +276,7 @@ int main(int argc, char **argv)
ksft_print_header();
ksft_set_plan(6);
- ksft_print_msg("Testing posix timers. False negative may happen on CPU execution \n");
+ ksft_print_msg("Testing posix timers. False negative may happen on CPU execution\n");
ksft_print_msg("based timers if other threads run on the CPU...\n");
if (check_itimer(ITIMER_VIRTUAL) < 0)
--
2.44.0.rc1.240.g4c46232300-goog
Fixes clang warning: absolute value function 'abs' given an argument of
type 'long long' but has parameter of type 'int' which may cause
truncation of value.
Signed-off-by: Edward Liaw <[email protected]>
---
tools/testing/selftests/timers/posix_timers.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/timers/posix_timers.c b/tools/testing/selftests/timers/posix_timers.c
index 0f550fc9e879..78b4b2d3dc44 100644
--- a/tools/testing/selftests/timers/posix_timers.c
+++ b/tools/testing/selftests/timers/posix_timers.c
@@ -82,7 +82,7 @@ static int check_diff(struct timeval start, struct timeval end)
diff = end.tv_usec - start.tv_usec;
diff += (end.tv_sec - start.tv_sec) * USECS_PER_SEC;
- if (abs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2)
+ if (llabs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2)
return -1;
return 0;
--
2.44.0.rc1.240.g4c46232300-goog
On Mon, Mar 04 2024 at 18:11, Edward Liaw wrote:
> I'm sending some patches that were orignally in
> https://lore.kernel.org/lkml/[email protected]/
> to prevent the timer_distribution test from hanging and also fix some
> format inconsistencies.
Thanks for picking those up and moving them forward. Any particular
reason why you didn't pick up the full set?
Thanks,
tglx
On Thu, Mar 07 2024 at 13:34, Edward Liaw wrote:
>> Thanks for picking those up and moving them forward. Any particular
>> reason why you didn't pick up the full set?
>
> I didn't know enough about the code to resolve some of the merges in the
> full set. I had run into the issue with the test timer_distribution test
> hanging on the Android kernel and wanted to get that fixed first.
Fair enough. I've marked your series for my post merge window tree and
I'll have a look at the rest of the pile.
Thanks,
tglx