#include "atimer.h"
#include <unistd.h>
+#ifdef HAVE_TIMERFD
+#include <sys/timerfd.h>
+#ifdef HAVE_TIMERFD_CLOEXEC
+#define TIMERFD_CREATE_FLAGS TFD_CLOEXEC
+#else
+#define TIMERFD_CREATE_FLAGS 0
+#endif /* HAVE_TIMERFD_CLOEXEC */
+#endif /* HAVE_TIMERFD */
+
/* Free-list of atimer structures. */
static struct atimer *free_atimers;
static struct atimer *atimers;
-/* The alarm timer and whether it was properly initialized, if
- POSIX timers are available. */
-#ifdef HAVE_ITIMERSPEC
+#if defined (HAVE_TIMERFD)
+/* File descriptor returned by timerfd_create. GNU/Linux-specific. */
+static int timerfd;
+#elif defined (HAVE_ITIMERSPEC)
+/* The alarm timer used if POSIX timers are available. */
static timer_t alarm_timer;
-static bool alarm_timer_ok;
+#endif
+
+#if defined (HAVE_TIMERFD) || defined (HAVE_ITIMERSPEC)
+/* Non-zero if one of the above was successfully initialized. Do not
+ use bool due to special treatment if HAVE_TIMERFD, see below. */
+static int special_timer_available;
+#endif
+
+#ifdef HAVE_CLOCK_GETRES
+/* Resolution of CLOCK_REALTIME clock. */
+static struct timespec resolution;
#endif
/* Block/unblock SIGALRM. */
struct atimer *t;
sigset_t oldset;
- /* Round TIME up to the next full second if we don't have
- itimers. */
-#ifndef HAVE_SETITIMER
+#if !defined (HAVE_SETITIMER)
+ /* Round TIME up to the next full second if we don't have itimers. */
if (timestamp.tv_nsec != 0 && timestamp.tv_sec < TYPE_MAXIMUM (time_t))
timestamp = make_timespec (timestamp.tv_sec + 1, 0);
+#elif defined (HAVE_CLOCK_GETRES)
+ /* Check that the system clock is precise enough. If
+ not, round TIME up to the system clock resolution. */
+ if (timespec_valid_p (resolution)
+ && timespec_cmp (timestamp, resolution) < 0)
+ timestamp = resolution;
#endif /* not HAVE_SETITIMER */
/* Get an atimer structure from the free-list, or allocate
#endif
struct timespec now, interval;
-#ifdef HAVE_ITIMERSPEC
- if (alarm_timer_ok)
+#if defined (HAVE_TIMERFD) || defined (HAVE_ITIMERSPEC)
+ if (special_timer_available)
{
struct itimerspec ispec;
ispec.it_value = atimers->expiration;
ispec.it_interval.tv_sec = ispec.it_interval.tv_nsec = 0;
- if (timer_settime (alarm_timer, 0, &ispec, 0) == 0)
+#if defined (HAVE_TIMERFD)
+ if (special_timer_available == 1)
+ {
+ add_timer_wait_descriptor (timerfd);
+ special_timer_available++;
+ }
+ if (timerfd_settime (timerfd, TFD_TIMER_ABSTIME, &ispec, 0) == 0)
+#elif defined (HAVE_ITIMERSPEC)
+ if (timer_settime (alarm_timer, TIMER_ABSTIME, &ispec, 0) == 0)
+#endif
return;
}
-#endif
+#endif /* HAVE_TIMERFD || HAVE_ITIMERSPEC */
/* Determine interval till the next timer is ripe.
Don't set the interval to 0; this disables the timer. */
pending_signals = 1;
}
+#ifdef HAVE_TIMERFD
+
+/* Called from wait_reading_process_output when FD, which
+ should be equal to TIMERFD, is available for reading. */
+
+void
+timerfd_callback (int fd, void *arg)
+{
+ char buf[8];
+ ptrdiff_t nbytes;
+
+ eassert (fd == timerfd);
+ nbytes = emacs_read (fd, buf, sizeof (buf));
+ /* Just discard an expiration count for now. */
+ eassert (nbytes == sizeof (buf));
+ do_pending_atimers ();
+}
+
+#endif /* HAVE_TIMERFD */
/* Do pending timers. */
if (on)
set_alarm ();
else
- alarm (0);
+ {
+#ifdef HAVE_TIMERFD
+ if (special_timer_available > 1)
+ {
+ struct itimerspec ispec;
+ memset (&ispec, 0, sizeof (ispec));
+ /* Writing zero expiration time should disarm it. */
+ timerfd_settime (timerfd, TFD_TIMER_ABSTIME, &ispec, 0);
+ }
+#endif /* HAVE_TIMERFD */
+ alarm (0);
+ }
}
+/* This is intended to use from automated tests. */
+
+#ifdef ENABLE_CHECKING
+
+#define MAXTIMERS 10
+
+struct atimer_result
+{
+ /* Time when we expect this timer to trigger. */
+ struct timespec expected;
+
+ /* Timer status: -1 if not triggered, 0 if triggered
+ too early or too late, 1 if triggered timely. */
+ int intime;
+};
+
+static void
+debug_timer_callback (struct atimer *t)
+{
+ struct timespec now = current_timespec ();
+ struct atimer_result *r = (struct atimer_result *) t->client_data;
+ int result = timespec_cmp (now, r->expected);
+
+ if (result < 0)
+ /* Too early. */
+ r->intime = 0;
+ else if (result >= 0)
+ {
+#ifdef HAVE_SETITIMER
+ struct timespec delta = timespec_sub (now, r->expected);
+ /* Too late if later than expected + 0.01s. FIXME:
+ this should depend from system clock resolution. */
+ if (timespec_cmp (delta, make_timespec (0, 10000000)) > 0)
+ r->intime = 0;
+ else
+#endif /* HAVE_SETITIMER */
+ r->intime = 1;
+ }
+}
+
+DEFUN ("debug-timer-check", Fdebug_timer_check, Sdebug_timer_check, 0, 0, 0,
+ doc: /* Run internal self-tests to check timers subsystem.
+Return t if all self-tests are passed, nil otherwise. */)
+ (void)
+{
+ int i, ok;
+ struct atimer *timer;
+ struct atimer_result *results[MAXTIMERS];
+ struct timespec t = make_timespec (0, 0);
+
+ /* Arm MAXTIMERS relative timers to trigger with 0.1s intervals. */
+ for (i = 0; i < MAXTIMERS; i++)
+ {
+ results[i] = xmalloc (sizeof (struct atimer_result));
+ t = timespec_add (t, make_timespec (0, 100000000));
+ results[i]->expected = timespec_add (current_timespec (), t);
+ results[i]->intime = -1;
+ timer = start_atimer (ATIMER_RELATIVE, t,
+ debug_timer_callback, results[i]);
+ }
+
+ /* Wait for 1s but process timers. */
+ wait_reading_process_output (1, 0, 0, false, Qnil, NULL, 0);
+ /* Shut up the compiler by "using" this variable. */
+ (void) timer;
+
+ for (i = 0, ok = 0; i < MAXTIMERS; i++)
+ ok += results[i]->intime, xfree (results[i]);
+
+ return ok == MAXTIMERS ? Qt : Qnil;
+}
+
+#endif /* ENABLE_CHECKING */
void
init_atimer (void)
{
-#ifdef HAVE_ITIMERSPEC
+#if defined (HAVE_TIMERFD)
+ timerfd = timerfd_create (CLOCK_REALTIME, TIMERFD_CREATE_FLAGS);
+ special_timer_available = !!(timerfd != -1);
+#elif defined (HAVE_ITIMERSPEC)
struct sigevent sigev;
sigev.sigev_notify = SIGEV_SIGNAL;
sigev.sigev_signo = SIGALRM;
sigev.sigev_value.sival_ptr = &alarm_timer;
- alarm_timer_ok = timer_create (CLOCK_REALTIME, &sigev, &alarm_timer) == 0;
-#endif
+ special_timer_available
+ = timer_create (CLOCK_REALTIME, &sigev, &alarm_timer) == 0;
+#endif /* HAVE_TIMERFD */
+#ifdef HAVE_CLOCK_GETRES
+ if (clock_getres (CLOCK_REALTIME, &resolution))
+ resolution = invalid_timespec ();
+#endif
free_atimers = stopped_atimers = atimers = NULL;
/* pending_signals is initialized in init_keyboard. */
struct sigaction action;
emacs_sigaction_init (&action, handle_alarm_signal);
sigaction (SIGALRM, &action, 0);
+
+#ifdef ENABLE_CHECKING
+ defsubr (&Sdebug_timer_check);
+#endif
}