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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2013 Red Hat, Inc., Frederic Weisbecker <fweisbec@redhat.com>
*
* Selftests for a few posix timers interface.
*
* Kernel loop code stolen from Steven Rostedt <srostedt@redhat.com>
*/
#include <sys/time.h>
#include <stdio.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <pthread.h>
#include "../kselftest.h"
#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 */
static void user_loop(void)
{
while (!done);
}
/*
* Try to spend as much time as possible in kernelspace
* to elapse ITIMER_PROF.
*/
static void kernel_loop(void)
{
void *addr = sbrk(0);
int err = 0;
while (!done && !err) {
err = brk(addr + 4096);
err |= brk(addr);
}
}
/*
* Sleep until ITIMER_REAL expiration.
*/
static void idle_loop(void)
{
pause();
}
static void sig_handler(int nr)
{
done = 1;
}
/*
* Check the expected timer expiration matches the GTOD elapsed delta since
* we armed the timer. Keep a 0.5 sec error margin due to various jitter.
*/
static int check_diff(struct timeval start, struct timeval end)
{
long long diff;
diff = end.tv_usec - start.tv_usec;
diff += (end.tv_sec - start.tv_sec) * USECS_PER_SEC;
if (llabs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2) {
printf("Diff too high: %lld..", diff);
return -1;
}
return 0;
}
static void check_itimer(int which, const char *name)
{
struct timeval start, end;
struct itimerval val = {
.it_value.tv_sec = DELAY,
};
done = 0;
if (which == ITIMER_VIRTUAL)
signal(SIGVTALRM, sig_handler);
else if (which == ITIMER_PROF)
signal(SIGPROF, sig_handler);
else if (which == ITIMER_REAL)
signal(SIGALRM, sig_handler);
if (gettimeofday(&start, NULL) < 0)
fatal_error(name, "gettimeofday()");
if (setitimer(which, &val, NULL) < 0)
fatal_error(name, "setitimer()");
if (which == ITIMER_VIRTUAL)
user_loop();
else if (which == ITIMER_PROF)
kernel_loop();
else if (which == ITIMER_REAL)
idle_loop();
if (gettimeofday(&end, NULL) < 0)
fatal_error(name, "gettimeofday()");
ksft_test_result(check_diff(start, end) == 0, "%s\n", name);
}
static void check_timer_create(int which, const char *name)
{
struct timeval start, end;
struct itimerspec val = {
.it_value.tv_sec = DELAY,
};
timer_t id;
done = 0;
if (timer_create(which, NULL, &id) < 0)
fatal_error(name, "timer_create()");
if (signal(SIGALRM, sig_handler) == SIG_ERR)
fatal_error(name, "signal()");
if (gettimeofday(&start, NULL) < 0)
fatal_error(name, "gettimeofday()");
if (timer_settime(id, 0, &val, NULL) < 0)
fatal_error(name, "timer_settime()");
user_loop();
if (gettimeofday(&end, NULL) < 0)
fatal_error(name, "gettimeofday()");
ksft_test_result(check_diff(start, end) == 0,
"timer_create() per %s\n", name);
}
static pthread_t ctd_thread;
static volatile int ctd_count, ctd_failed;
static void ctd_sighandler(int sig)
{
if (pthread_self() != ctd_thread)
ctd_failed = 1;
ctd_count--;
}
static void *ctd_thread_func(void *arg)
{
struct itimerspec val = {
.it_value.tv_sec = 0,
.it_value.tv_nsec = 1000 * 1000,
.it_interval.tv_sec = 0,
.it_interval.tv_nsec = 1000 * 1000,
};
timer_t id;
/* 1/10 seconds to ensure the leader sleeps */
usleep(10000);
ctd_count = 100;
if (timer_create(CLOCK_PROCESS_CPUTIME_ID, NULL, &id))
fatal_error(NULL, "timer_create()");
if (timer_settime(id, 0, &val, NULL))
fatal_error(NULL, "timer_settime()");
while (ctd_count > 0 && !ctd_failed)
;
if (timer_delete(id))
fatal_error(NULL, "timer_delete()");
return NULL;
}
/*
* Test that only the running thread receives the timer signal.
*/
static void check_timer_distribution(void)
{
if (signal(SIGALRM, ctd_sighandler) == SIG_ERR)
fatal_error(NULL, "signal()");
if (pthread_create(&ctd_thread, NULL, ctd_thread_func, NULL))
fatal_error(NULL, "pthread_create()");
if (pthread_join(ctd_thread, NULL))
fatal_error(NULL, "pthread_join()");
if (!ctd_failed)
ksft_test_result_pass("check signal distribution\n");
else if (ksft_min_kernel_version(6, 3))
ksft_test_result_fail("check signal distribution\n");
else
ksft_test_result_skip("check signal distribution (old kernel)\n");
}
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("based timers if other threads run on the CPU...\n");
check_itimer(ITIMER_VIRTUAL, "ITIMER_VIRTUAL");
check_itimer(ITIMER_PROF, "ITIMER_PROF");
check_itimer(ITIMER_REAL, "ITIMER_REAL");
check_timer_create(CLOCK_THREAD_CPUTIME_ID, "CLOCK_THREAD_CPUTIME_ID");
/*
* It's unfortunately hard to reliably test a timer expiration
* on parallel multithread cputime. We could arm it to expire
* on DELAY * nr_threads, with nr_threads busy looping, then wait
* the normal DELAY since the time is elapsing nr_threads faster.
* But for that we need to ensure we have real physical free CPUs
* to ensure true parallelism. So test only one thread until we
* find a better solution.
*/
check_timer_create(CLOCK_PROCESS_CPUTIME_ID, "CLOCK_PROCESS_CPUTIME_ID");
check_timer_distribution();
ksft_finished();
}
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