[PATCH v1 0/3] selftests/timers/posix_timers: various cleanups

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* [PATCH v1 0/3] selftests/timers/posix_timers: various cleanups
@ 2024-03-04 18:11 Edward Liaw
  2024-03-04 18:11 ` [PATCH v1 1/3] selftests/timers/posix_timers: Make signal distribution test less fragile Edward Liaw
                   ` (3 more replies)
  0 siblings, 4 replies; 6+ messages in thread
From: Edward Liaw @ 2024-03-04 18:11 UTC (permalink / raw)
  To: linux-kernel, John Stultz, Thomas Gleixner, Stephen Boyd,
	Shuah Khan, Nathan Chancellor, Nick Desaulniers, Bill Wendling,
	Justin Stitt
  Cc: linux-kselftest, kernel-team, Edward Liaw, llvm

I'm sending some patches that were orignally in
https://lore.kernel.org/lkml/20230606132949.068951363@linutronix.de/
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


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH v1 1/3] selftests/timers/posix_timers: Make signal distribution test less fragile
  2024-03-04 18:11 [PATCH v1 0/3] selftests/timers/posix_timers: various cleanups Edward Liaw
@ 2024-03-04 18:11 ` Edward Liaw
  2024-03-04 18:11 ` [PATCH v1 2/3] selftests/timers/posix_timers: Use TAP reporting format Edward Liaw
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 6+ messages in thread
From: Edward Liaw @ 2024-03-04 18:11 UTC (permalink / raw)
  To: linux-kernel, John Stultz, Thomas Gleixner, Stephen Boyd,
	Shuah Khan, Nathan Chancellor, Nick Desaulniers, Bill Wendling,
	Justin Stitt
  Cc: linux-kselftest, kernel-team, Edward Liaw, llvm

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 <tglx@linutronix.de>
[edliaw: Rebase and fix checkpatch recommendations]
Signed-off-by: Edward Liaw <edliaw@google.com>
---
 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


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH v1 2/3] selftests/timers/posix_timers: Use TAP reporting format
  2024-03-04 18:11 [PATCH v1 0/3] selftests/timers/posix_timers: various cleanups Edward Liaw
  2024-03-04 18:11 ` [PATCH v1 1/3] selftests/timers/posix_timers: Make signal distribution test less fragile Edward Liaw
@ 2024-03-04 18:11 ` Edward Liaw
  2024-03-04 18:11 ` [PATCH v1 3/3] selftests/timers/posix_timers: Use llabs for long long Edward Liaw
  2024-03-07 21:04 ` [PATCH v1 0/3] selftests/timers/posix_timers: various cleanups Thomas Gleixner
  3 siblings, 0 replies; 6+ messages in thread
From: Edward Liaw @ 2024-03-04 18:11 UTC (permalink / raw)
  To: linux-kernel, John Stultz, Thomas Gleixner, Stephen Boyd,
	Shuah Khan, Nathan Chancellor, Nick Desaulniers, Bill Wendling,
	Justin Stitt
  Cc: linux-kselftest, kernel-team, Edward Liaw, llvm

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[edliaw: Fix checkpatch recommendations]
Signed-off-by: Edward Liaw <edliaw@google.com>
---
 tools/testing/selftests/timers/posix_timers.c | 161 +++++++-----------
 1 file changed, 66 insertions(+), 95 deletions(-)

diff --git a/tools/testing/selftests/timers/posix_timers.c b/tools/testing/selftests/timers/posix_timers.c
index 03779b6b3c20..0f550fc9e879 100644
--- a/tools/testing/selftests/timers/posix_timers.c
+++ b/tools/testing/selftests/timers/posix_timers.c
@@ -10,6 +10,7 @@
 #include <sys/time.h>
 #include <stdio.h>
 #include <signal.h>
+#include <string.h>
 #include <unistd.h>
 #include <time.h>
 #include <pthread.h>
@@ -19,6 +20,20 @@
 #define DELAY 2
 #define USECS_PER_SEC 1000000
 
+static void __fatal_error(const char *test, const char *name, const char *what)
+{
+	char buf[64];
+
+	strerror_r(errno, buf, sizeof(buf));
+
+	if (name && strlen(name))
+		ksft_exit_fail_msg("%s %s %s %s\n", test, name, what, buf);
+	else
+		ksft_exit_fail_msg("%s %s %s\n", test, what, buf);
+}
+
+#define fatal_error(name, what)		__fatal_error(__func__, name, what)
+
 static volatile int done;
 
 /* Busy loop in userspace to elapse ITIMER_VIRTUAL */
@@ -67,15 +82,13 @@ 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) {
-		printf("Diff too high: %lld..", diff);
+	if (abs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2)
 		return -1;
-	}
 
 	return 0;
 }
 
-static int check_itimer(int which)
+static void check_itimer(int which)
 {
 	const char *name;
 	int err;
@@ -91,7 +104,7 @@ static int check_itimer(int which)
 	else if (which == ITIMER_REAL)
 		name = "ITIMER_REAL";
 	else
-		return -1;
+		ksft_exit_fail_msg("Unknown setitimer() type %d\n", which);
 
 	done = 0;
 
@@ -103,16 +116,12 @@ static int check_itimer(int which)
 		signal(SIGALRM, sig_handler);
 
 	err = gettimeofday(&start, NULL);
-	if (err < 0) {
-		ksft_perror("Can't call gettimeofday()");
-		return -1;
-	}
+	if (err < 0)
+		fatal_error(name, "gettimeofday()");
 
 	err = setitimer(which, &val, NULL);
-	if (err < 0) {
-		ksft_perror("Can't set timer");
-		return -1;
-	}
+	if (err < 0)
+		fatal_error(name, "setitimer()");
 
 	if (which == ITIMER_VIRTUAL)
 		user_loop();
@@ -122,19 +131,15 @@ static int check_itimer(int which)
 		idle_loop();
 
 	err = gettimeofday(&end, NULL);
-	if (err < 0) {
-		ksft_perror("Can't call gettimeofday()");
-		return -1;
-	}
+	if (err < 0)
+		fatal_error(name, "gettimeofday()");
 
-	ksft_test_result(check_diff(start, end) == 0, "%s\n", name);
-
-	return 0;
+	ksft_test_result(!check_diff(start, end), "%s %s\n", __func__, name);
 }
 
-static int check_timer_create(int which)
+static void check_timer_create(int which)
 {
-	const char *type;
+	const char *name;
 	int err;
 	timer_t id;
 	struct timeval start, end;
@@ -142,47 +147,37 @@ static int check_timer_create(int which)
 		.it_value.tv_sec = DELAY,
 	};
 
-	if (which == CLOCK_THREAD_CPUTIME_ID) {
-		type = "thread";
-	} else if (which == CLOCK_PROCESS_CPUTIME_ID) {
-		type = "process";
-	} else {
-		ksft_print_msg("Unknown timer_create() type %d\n", which);
-		return -1;
-	}
+	if (which == CLOCK_THREAD_CPUTIME_ID)
+		name = "thread";
+	else if (which == CLOCK_PROCESS_CPUTIME_ID)
+		name = "process";
+	else
+		ksft_exit_fail_msg("Unknown timer_create() type %d\n", which);
 
 	done = 0;
 	err = timer_create(which, NULL, &id);
-	if (err < 0) {
-		ksft_perror("Can't create timer");
-		return -1;
-	}
-	signal(SIGALRM, sig_handler);
+	if (err < 0)
+		fatal_error(name, "timer_create()");
+
+	if (signal(SIGALRM, sig_handler) == SIG_ERR)
+		fatal_error(name, "signal()");
 
 	err = gettimeofday(&start, NULL);
-	if (err < 0) {
-		ksft_perror("Can't call gettimeofday()");
-		return -1;
-	}
+	if (err < 0)
+		fatal_error(name, "gettimeofday()");
 
 	err = timer_settime(id, 0, &val, NULL);
-	if (err < 0) {
-		ksft_perror("Can't set timer");
-		return -1;
-	}
+	if (err < 0)
+		fatal_error(name, "timer_settime()");
 
 	user_loop();
 
 	err = gettimeofday(&end, NULL);
-	if (err < 0) {
-		ksft_perror("Can't call gettimeofday()");
-		return -1;
-	}
+	if (err < 0)
+		fatal_error(name, "gettimeofday()");
 
 	ksft_test_result(check_diff(start, end) == 0,
-			 "timer_create() per %s\n", type);
-
-	return 0;
+			 "%s %s\n", __func__, name);
 }
 
 static int remain;
@@ -205,7 +200,7 @@ static void distribution_handler(int nr)
  * Test that all running threads _eventually_ receive CLOCK_PROCESS_CPUTIME_ID
  * timer signals. This primarily tests that the kernel does not favour any one.
  */
-static int check_timer_distribution(void)
+static void check_timer_distribution(void)
 {
 	const int nthreads = 10;
 	pthread_t threads[nthreads];
@@ -221,26 +216,20 @@ static int check_timer_distribution(void)
 
 	done = 0;
 	remain = nthreads + 1;  /* worker threads + this thread */
-	signal(SIGALRM, distribution_handler);
+	if (signal(SIGALRM, distribution_handler) == SIG_ERR)
+		fatal_error(NULL, "signal()");
+
 	err = timer_create(CLOCK_PROCESS_CPUTIME_ID, NULL, &id);
-	if (err < 0) {
-		ksft_perror("Can't create timer");
-		return -1;
-	}
+	if (err < 0)
+		fatal_error(NULL, "timer_create()");
+
 	err = timer_settime(id, 0, &val, NULL);
-	if (err < 0) {
-		ksft_perror("Can't set timer");
-		return -1;
-	}
+	if (err < 0)
+		fatal_error(NULL, "timer_settime()");
 
 	for (i = 0; i < nthreads; i++) {
-		err = pthread_create(&threads[i], NULL, distribution_thread,
-				     NULL);
-		if (err) {
-			ksft_print_msg("Can't create thread: %s (%d)\n",
-				       strerror(errno), errno);
-			return -1;
-		}
+		if (pthread_create(&threads[i], NULL, distribution_thread, NULL))
+			fatal_error(NULL, "pthread_create()");
 	}
 
 	/* Wait for all threads to receive the signal. */
@@ -252,23 +241,15 @@ static int check_timer_distribution(void)
 	}
 	done = 1;
 
-	if (timer_delete(id)) {
-		ksft_perror("Can't delete timer\n");
-		return -1;
-	}
+	if (timer_delete(id))
+		fatal_error(NULL, "timer_delete()");
 
 	for (i = 0; i < nthreads; i++) {
-		err = pthread_join(threads[i], NULL);
-		if (err) {
-			ksft_print_msg("Can't join thread: %s (%d)\n",
-				       strerror(errno), errno);
-			return -1;
-		}
+		if (pthread_join(threads[i], NULL))
+			fatal_error(NULL, "pthread_join()");
 	}
 
 	ksft_test_result((now - start <= 5), "%s\n", __func__);
-
-	return 0;
 }
 
 int main(int argc, char **argv)
@@ -279,17 +260,10 @@ int main(int argc, char **argv)
 	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)
-		return ksft_exit_fail();
-
-	if (check_itimer(ITIMER_PROF) < 0)
-		return ksft_exit_fail();
-
-	if (check_itimer(ITIMER_REAL) < 0)
-		return ksft_exit_fail();
-
-	if (check_timer_create(CLOCK_THREAD_CPUTIME_ID) < 0)
-		return ksft_exit_fail();
+	check_itimer(ITIMER_VIRTUAL);
+	check_itimer(ITIMER_PROF);
+	check_itimer(ITIMER_REAL);
+	check_timer_create(CLOCK_THREAD_CPUTIME_ID);
 
 	/*
 	 * It's unfortunately hard to reliably test a timer expiration
@@ -300,11 +274,8 @@ int main(int argc, char **argv)
 	 * to ensure true parallelism. So test only one thread until we
 	 * find a better solution.
 	 */
-	if (check_timer_create(CLOCK_PROCESS_CPUTIME_ID) < 0)
-		return ksft_exit_fail();
-
-	if (check_timer_distribution() < 0)
-		return ksft_exit_fail();
+	check_timer_create(CLOCK_PROCESS_CPUTIME_ID);
+	check_timer_distribution();
 
 	ksft_finished();
 }
-- 
2.44.0.rc1.240.g4c46232300-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH v1 3/3] selftests/timers/posix_timers: Use llabs for long long
  2024-03-04 18:11 [PATCH v1 0/3] selftests/timers/posix_timers: various cleanups Edward Liaw
  2024-03-04 18:11 ` [PATCH v1 1/3] selftests/timers/posix_timers: Make signal distribution test less fragile Edward Liaw
  2024-03-04 18:11 ` [PATCH v1 2/3] selftests/timers/posix_timers: Use TAP reporting format Edward Liaw
@ 2024-03-04 18:11 ` Edward Liaw
  2024-03-07 21:04 ` [PATCH v1 0/3] selftests/timers/posix_timers: various cleanups Thomas Gleixner
  3 siblings, 0 replies; 6+ messages in thread
From: Edward Liaw @ 2024-03-04 18:11 UTC (permalink / raw)
  To: linux-kernel, John Stultz, Thomas Gleixner, Stephen Boyd,
	Shuah Khan, Nathan Chancellor, Nick Desaulniers, Bill Wendling,
	Justin Stitt
  Cc: linux-kselftest, kernel-team, Edward Liaw, llvm

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 <edliaw@google.com>
---
 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


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH v1 0/3] selftests/timers/posix_timers: various cleanups
  2024-03-04 18:11 [PATCH v1 0/3] selftests/timers/posix_timers: various cleanups Edward Liaw
                   ` (2 preceding siblings ...)
  2024-03-04 18:11 ` [PATCH v1 3/3] selftests/timers/posix_timers: Use llabs for long long Edward Liaw
@ 2024-03-07 21:04 ` Thomas Gleixner
       [not found]   ` <CAG4es9XXYzzrt3-eybtXZ2Cy9fTtEPiCbggDxPcaRY=fiKM78A@mail.gmail.com>
  3 siblings, 1 reply; 6+ messages in thread
From: Thomas Gleixner @ 2024-03-07 21:04 UTC (permalink / raw)
  To: Edward Liaw, linux-kernel, John Stultz, Stephen Boyd, Shuah Khan,
	Nathan Chancellor, Nick Desaulniers, Bill Wendling, Justin Stitt
  Cc: linux-kselftest, kernel-team, Edward Liaw, llvm

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/20230606132949.068951363@linutronix.de/
> 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

^ permalink raw reply	[flat|nested] 6+ messages in thread

[parent not found: <CAG4es9XXYzzrt3-eybtXZ2Cy9fTtEPiCbggDxPcaRY=fiKM78A@mail.gmail.com>]

* Re: [PATCH v1 0/3] selftests/timers/posix_timers: various cleanups
       [not found]   ` <CAG4es9XXYzzrt3-eybtXZ2Cy9fTtEPiCbggDxPcaRY=fiKM78A@mail.gmail.com>
@ 2024-03-07 21:41     ` Thomas Gleixner
  0 siblings, 0 replies; 6+ messages in thread
From: Thomas Gleixner @ 2024-03-07 21:41 UTC (permalink / raw)
  To: Edward Liaw
  Cc: linux-kernel, John Stultz, Stephen Boyd, Shuah Khan,
	Nathan Chancellor, Nick Desaulniers, Bill Wendling, Justin Stitt,
	linux-kselftest, kernel-team, llvm

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


^ permalink raw reply	[flat|nested] 6+ messages in thread

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2024-03-04 18:11 ` [PATCH v1 1/3] selftests/timers/posix_timers: Make signal distribution test less fragile Edward Liaw
2024-03-04 18:11 ` [PATCH v1 2/3] selftests/timers/posix_timers: Use TAP reporting format Edward Liaw
2024-03-04 18:11 ` [PATCH v1 3/3] selftests/timers/posix_timers: Use llabs for long long Edward Liaw
2024-03-07 21:04 ` [PATCH v1 0/3] selftests/timers/posix_timers: various cleanups Thomas Gleixner
     [not found]   ` <CAG4es9XXYzzrt3-eybtXZ2Cy9fTtEPiCbggDxPcaRY=fiKM78A@mail.gmail.com>
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