Commit 263dda24 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Thomas Gleixner
Browse files

selftests/proc: Assert clock_gettime(CLOCK_BOOTTIME) VS /proc/uptime monotonicity 



The first field of /proc/uptime relies on the CLOCK_BOOTTIME clock which
can also be fetched from clock_gettime() API.

Improve the test coverage while verifying the monotonicity of
CLOCK_BOOTTIME accross both interfaces.

Suggested-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230222144649.624380-9-frederic@kernel.org
parent 270b2a67

tools/testing/selftests/proc/proc-uptime-001.c

+17 −4
Original line number Diff line number Diff line
@@ -13,9 +13,9 @@ 
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

// Test that boottime value in /proc/uptime increments monotonically.

// We don't test idle time monotonicity due to broken iowait task

// counting, cf: comment above get_cpu_idle_time_us()

// Test that boottime value in /proc/uptime and CLOCK_BOOTTIME increment

// monotonically. We don't test idle time monotonicity due to broken iowait

// task counting, cf: comment above get_cpu_idle_time_us()

#undef NDEBUG

#include <assert.h>

#include <stdint.h>
@@ -27,7 +27,7 @@ 


int main(void)

{

	uint64_t start, u0, u1;

	uint64_t start, u0, u1, c0, c1;

	int fd;



	fd = open("/proc/uptime", O_RDONLY);
@@ -35,10 +35,23 @@ int main(void) 


	u0 = proc_uptime(fd);

	start = u0;

	c0 = clock_boottime();



	do {

		u1 = proc_uptime(fd);

		c1 = clock_boottime();



		/* Is /proc/uptime monotonic ? */

		assert(u1 >= u0);



		/* Is CLOCK_BOOTTIME monotonic ? */

		assert(c1 >= c0);



		/* Is CLOCK_BOOTTIME VS /proc/uptime monotonic ? */

		assert(c0 >= u0);



		u0 = u1;

		c0 = c1;

	} while (u1 - start < 100);



	return 0;

tools/testing/selftests/proc/proc-uptime-002.c

+18 −4
Original line number Diff line number Diff line
@@ -13,9 +13,10 @@ 
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

// Test that boottime value in /proc/uptime increments monotonically

// while shifting across CPUs. We don't test idle time monotonicity

// due to broken iowait task counting, cf: comment above get_cpu_idle_time_us()

// Test that boottime value in /proc/uptime and CLOCK_BOOTTIME increment

// monotonically while shifting across CPUs. We don't test idle time

// monotonicity due to broken iowait task counting, cf: comment above

// get_cpu_idle_time_us()

#undef NDEBUG

#include <assert.h>

#include <errno.h>
@@ -43,10 +44,10 @@ static inline int sys_sched_setaffinity(pid_t pid, unsigned int len, unsigned lo 


int main(void)

{

	uint64_t u0, u1, c0, c1;

	unsigned int len;

	unsigned long *m;

	unsigned int cpu;

	uint64_t u0, u1;

	int fd;



	/* find out "nr_cpu_ids" */
@@ -62,6 +63,8 @@ int main(void) 
	assert(fd >= 0);



	u0 = proc_uptime(fd);

	c0 = clock_boottime();



	for (cpu = 0; cpu < len * 8; cpu++) {

		memset(m, 0, len);

		m[cpu / (8 * sizeof(unsigned long))] |= 1UL << (cpu % (8 * sizeof(unsigned long)));
@@ -70,8 +73,19 @@ int main(void) 
		sys_sched_setaffinity(0, len, m);



		u1 = proc_uptime(fd);

		c1 = clock_boottime();



		/* Is /proc/uptime monotonic ? */

		assert(u1 >= u0);



		/* Is CLOCK_BOOTTIME monotonic ? */

		assert(c1 >= c0);



		/* Is CLOCK_BOOTTIME VS /proc/uptime monotonic ? */

		assert(c0 >= u0);



		u0 = u1;

		c0 = c1;

	}



	return 0;

tools/testing/selftests/proc/proc-uptime.h

+12 −0
Original line number Diff line number Diff line
@@ -19,9 +19,21 @@ 
#include <string.h>

#include <stdlib.h>

#include <unistd.h>

#include <time.h>



#include "proc.h"



static uint64_t clock_boottime(void)

{

	struct timespec ts;

	int err;



	err = clock_gettime(CLOCK_BOOTTIME, &ts);

	assert(err >= 0);



	return (ts.tv_sec * 100) + (ts.tv_nsec / 10000000);

}



static uint64_t proc_uptime(int fd)

{

	uint64_t val1, val2;