UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

selftests/proc: Remove idle time monotonicity assertions 

Due to broken iowait task counting design (cf: comments above
get_cpu_idle_time_us() and nr_iowait()), it is not possible to provide
the guarantee that /proc/stat or /proc/uptime display monotonic idle
time values.

Remove the assertions that verify the related wrong assumption so that
testers and maintainers don't spend more time on that.

Reported-by: Yu Liao <liaoyu15@huawei.com>
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230222144649.624380-8-frederic@kernel.org
This commit is contained in:
Frederic Weisbecker 2023-02-22 15:46:48 +01:00 committed by Thomas Gleixner
parent 9a1d4b8a7b
commit 270b2a679e
3 changed files with 14 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
tools/testing/selftests/proc/proc-uptime-001.c
View File

@ -13,7 +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 values in /proc/uptime increment monotonically.
// 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()
#undef NDEBUG
#include <assert.h>
#include <stdint.h>
@ -25,20 +27,18 @@
int main(void)
{
uint64_t start, u0, u1, i0, i1;
uint64_t start, u0, u1;
int fd;
fd = open("/proc/uptime", O_RDONLY);
assert(fd >= 0);
proc_uptime(fd, &u0, &i0);
u0 = proc_uptime(fd);
start = u0;
do {
proc_uptime(fd, &u1, &i1);
u1 = proc_uptime(fd);
assert(u1 >= u0);
assert(i1 >= i0);
u0 = u1;
i0 = i1;
} while (u1 - start < 100);
return 0;

13
tools/testing/selftests/proc/proc-uptime-002.c
View File

@ -13,8 +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 values in /proc/uptime increment monotonically
// while shifting across CPUs.
// 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()
#undef NDEBUG
#include <assert.h>
#include <errno.h>
@ -45,7 +46,7 @@ int main(void)
unsigned int len;
unsigned long *m;
unsigned int cpu;
uint64_t u0, u1, i0, i1;
uint64_t u0, u1;
int fd;
/* find out "nr_cpu_ids" */
@ -60,7 +61,7 @@ int main(void)
fd = open("/proc/uptime", O_RDONLY);
assert(fd >= 0);
proc_uptime(fd, &u0, &i0);
u0 = proc_uptime(fd);
for (cpu = 0; cpu < len * 8; cpu++) {
memset(m, 0, len);
m[cpu / (8 * sizeof(unsigned long))] |= 1UL << (cpu % (8 * sizeof(unsigned long)));
@ -68,11 +69,9 @@ int main(void)
/* CPU might not exist, ignore error */
sys_sched_setaffinity(0, len, m);
proc_uptime(fd, &u1, &i1);
u1 = proc_uptime(fd);
assert(u1 >= u0);
assert(i1 >= i0);
u0 = u1;
i0 = i1;
}
return 0;

16
tools/testing/selftests/proc/proc-uptime.h
View File

@ -22,7 +22,7 @@
#include "proc.h"
static void proc_uptime(int fd, uint64_t *uptime, uint64_t *idle)
static uint64_t proc_uptime(int fd)
{
uint64_t val1, val2;
char buf[64], *p;
@ -43,18 +43,6 @@ static void proc_uptime(int fd, uint64_t *uptime, uint64_t *idle)
assert(p[3] == ' ');
val2 = (p[1] - '0') * 10 + p[2] - '0';
*uptime = val1 * 100 + val2;
p += 4;
val1 = xstrtoull(p, &p);
assert(p[0] == '.');
assert('0' <= p[1] && p[1] <= '9');
assert('0' <= p[2] && p[2] <= '9');
assert(p[3] == '\n');
val2 = (p[1] - '0') * 10 + p[2] - '0';
*idle = val1 * 100 + val2;
assert(p + 4 == buf + rv);
return val1 * 100 + val2;
}