From: Richard Weinberger <richard.weinberger@gmail.com>
To: "Petr Červenka" <grugh@centrum.cz>
Cc: Jan Kiszka <jan.kiszka@siemens.com>, Xenomai <xenomai@xenomai.org>
Subject: Re: rt_task_unblock() POSIX alternative
Date: Thu, 9 Apr 2020 18:13:37 +0200 [thread overview]
Message-ID: <CAFLxGvy8SP+4mr3PYYRHuxww=22w28RjaDPUgDSVFVHx-_cQ_g@mail.gmail.com> (raw)
In-Reply-To: <20200409170009.5B0DAA77@centrum.cz>
On Thu, Apr 9, 2020 at 5:00 PM Petr Červenka <grugh@centrum.cz> wrote:
>
> > 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);
Don't use signal().
Use sigaction() and *don't* set SA_RESTART. Maybe read() is always restarted...
--
Thanks,
//richard
next prev parent reply other threads:[~2020-04-09 16:13 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
2020-04-09 16:13 ` Richard Weinberger [this message]
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
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