From: "Petr Červenka" <grugh@centrum.cz>
To: "Richard Weinberger" <richard.weinberger@gmail.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>, Xenomai <xenomai@xenomai.org>
Subject: Re: rt_task_unblock() POSIX alternative
Date: Thu, 09 Apr 2020 17:00:09 +0200 [thread overview]
Message-ID: <20200409170009.5B0DAA77@centrum.cz> (raw)
In-Reply-To: <CAFLxGvx9-awne2He+ULqOzwf0cGae1s_k+-b8tdiM+uT67+cYg@mail.gmail.com>
> BTW:
> Why do you think nothing can interrupt a read() from a timerfd?
> If read() blocks on a timerfd the calling thread will be put into
> interruptable sleep.
"I" was not able to send a signal to the task and interrupt it.
Here is an example. Please let me know, how to improve it to interrupt the read() before its timeout:
#include <math.h>
#include <pthread.h>
#include <stdint.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/timerfd.h>
#include <unistd.h>
#define AUTO_KILL
#define SECOND 1000000000l // ns
#define PERIOD (5 * SECOND) // ns
#define SLEEP (1 * SECOND) // ns
using namespace std;
static pid_t mainTask_pid;
static pthread_t task;
static int timer_fd;
static bool end = false;
void signalHandler(int signal) {
int err;
printf("Signal handler: %d\n", signal);
end = true;
err = pthread_kill(task, SIGINT);
if (err != 0) {
printf("pthread_kill failed: %d (%s)\n", err, strerror(-err));
}
printf("Signal handler end\n");
}
void timediff (struct timespec *result, const struct timespec *t1, const struct timespec *t2) {
result->tv_sec = t2->tv_sec - t1->tv_sec;
result->tv_nsec = t2->tv_nsec - t1->tv_nsec;
if (result->tv_nsec >= SECOND) {
result->tv_nsec -= SECOND;
result->tv_sec++;
}
if (result->tv_nsec < 0) {
result->tv_nsec += SECOND;
result->tv_sec--;
}
}
static void *taskHandler(void *cookie) {
int err;
printf("Task started\n");
signal(SIGINT, signalHandler);
signal(SIGTERM, signalHandler);
// Get current time
struct timespec start;
clock_gettime(CLOCK_MONOTONIC, &start);
// Set task period
timer_fd = timerfd_create(CLOCK_MONOTONIC, 0);
struct itimerspec timer_conf;
timer_conf.it_value.tv_sec = start.tv_sec;
timer_conf.it_value.tv_nsec = start.tv_nsec;
timer_conf.it_interval.tv_sec = PERIOD / SECOND;
timer_conf.it_interval.tv_nsec = PERIOD % SECOND;
printf("Set period: %.3gs\n", timer_conf.it_interval.tv_sec + (double) timer_conf.it_interval.tv_nsec / SECOND);
err = timerfd_settime(timer_fd, TFD_TIMER_ABSTIME, &timer_conf, NULL);
if (err != 0) {
printf("timerfd_settime failed: %d (%s)\n", err, strerror(-err));
return NULL;
}
// Main cycle
while (!end) {
// Wait next period
uint64_t ticks;
::read(timer_fd, &ticks, sizeof (ticks));
// Get current time
struct timespec now, result;
clock_gettime(CLOCK_MONOTONIC, &now);
// Printf wait time
timediff(&result, &start, &now);
printf("Task livind: %.3gs\n", result.tv_sec + (double) result.tv_nsec / SECOND);
start = now;
}
::close(timer_fd);
printf("Task ended\n");
}
/*
*
*/
int main(int argc, char** argv) {
unsigned long overruns;
int err;
mlockall(MCL_CURRENT | MCL_FUTURE);
// Setup signal handler
signal(SIGINT, signalHandler);
signal(SIGTERM, signalHandler);
// Get current process ID
mainTask_pid = getpid();
// Make main task real-time (prio 1)
sched_param param;
memset(¶m, 0, sizeof(param));
param.sched_priority = 1;
err = sched_setscheduler(mainTask_pid, SCHED_FIFO, ¶m);
if (err != 0) {
printf("sched_setscheduler failed: %d (%s)\n", err, strerror(-err));
goto sched_setscheduler_err;
}
// Create new task (prio 2)
pthread_attr_t tattr;
pthread_attr_init(&tattr);
pthread_attr_setinheritsched(&tattr, PTHREAD_EXPLICIT_SCHED);
pthread_attr_setschedpolicy(&tattr, SCHED_FIFO);
memset(¶m, 0, sizeof (param));
param.sched_priority = 2;
pthread_attr_setschedparam(&tattr, ¶m);
err = pthread_create(&task, &tattr, taskHandler, NULL);
if (err != 0) {
printf("pthread_create failed: %d (%s)\n", err, strerror(-err));
goto pthread_create_err;
}
#ifndef AUTO_KILL
printf("Press ^C to stop!\n");
do {
pause();
} while(!end);
#else
usleep(SLEEP / 1000);
// Call of signal handler
err = kill(0, SIGINT); // THE ONLY ONE WHICH WORKS !!!
//err = kill(getpid(), SIGINT);
//err = kill(mainTask_pid, SIGINT);
//err = pthread_kill(pthread_self(), SIGINT);
//err = pthread_kill(task, SIGINT);
if (err != 0) {
printf("pthread_kill failed: %d (%s)\n", err, strerror(-err));
}
#endif
printf("Waiting for join\n");
//pthread_cancel(task);
pthread_join(task, NULL);
pthread_create_err:
sched_setaffinity_err:
sched_setscheduler_err:
return 0;
}
next prev parent reply other threads:[~2020-04-09 15:00 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-07 13:41 rt_task_unblock() POSIX alternative Petr Červenka
2020-04-07 14:59 ` Jan Kiszka
2020-04-07 15:18 ` Petr Červenka
2020-04-07 15:29 ` Jan Kiszka
2020-04-07 15:30 ` Richard Weinberger
2020-04-08 9:44 ` Petr Červenka
2020-04-08 10:06 ` Richard Weinberger
2020-04-08 21:36 ` Richard Weinberger
2020-04-09 15:00 ` Petr Červenka [this message]
2020-04-09 16:13 ` Richard Weinberger
2020-04-09 18:10 ` Petr Červenka
2020-04-09 18:48 ` Richard Weinberger
2020-04-14 8:16 ` Petr Červenka
2020-04-14 8:30 ` Richard Weinberger
2020-04-14 9:10 ` Petr Červenka
2020-04-14 9:46 ` Richard Weinberger
2020-04-14 10:07 ` Jan Kiszka
2020-04-14 10:23 ` Richard Weinberger
2020-04-14 10:28 ` Jan Kiszka
2020-04-14 10:41 ` Richard Weinberger
2020-04-14 10:43 ` Jan Kiszka
2020-04-14 10:56 ` Richard Weinberger
2020-04-14 11:01 ` Jan Kiszka
2020-04-14 11:05 ` Richard Weinberger
2020-04-14 11:30 ` Jan Kiszka
2020-04-14 10:39 ` Petr Červenka
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200409170009.5B0DAA77@centrum.cz \
--to=grugh@centrum.cz \
--cc=jan.kiszka@siemens.com \
--cc=richard.weinberger@gmail.com \
--cc=xenomai@xenomai.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.