#include "atimer.h"
#include <unistd.h>
+#ifdef HAVE_TIMERFD
+#include <errno.h>
+# include <sys/timerfd.h>
+#endif
+
/* Free-list of atimer structures. */
static struct atimer *free_atimers;
static struct atimer *atimers;
+#ifdef HAVE_ITIMERSPEC
/* The alarm timer and whether it was properly initialized, if
POSIX timers are available. */
-#ifdef HAVE_ITIMERSPEC
static timer_t alarm_timer;
static bool alarm_timer_ok;
+
+# ifdef HAVE_TIMERFD
+/* File descriptor for timer, or -1 if it could not be created. */
+static int timerfd;
+# else
+enum { timerfd = -1 };
+# endif
#endif
/* Block/unblock SIGALRM. */
static struct atimer *append_atimer_lists (struct atimer *,
struct atimer *);
-/* Start a new atimer of type TYPE. TIME specifies when the timer is
+/* Start a new atimer of type TYPE. TIMESTAMP specifies when the timer is
ripe. FN is the function to call when the timer fires.
CLIENT_DATA is stored in the client_data member of the atimer
structure returned and so made available to FN when it is called.
- If TYPE is ATIMER_ABSOLUTE, TIME is the absolute time at which the
+ If TYPE is ATIMER_ABSOLUTE, TIMESTAMP is the absolute time at which the
timer fires.
- If TYPE is ATIMER_RELATIVE, the timer is ripe TIME s/us in the
+ If TYPE is ATIMER_RELATIVE, the timer is ripe TIMESTAMP seconds in the
future.
In both cases, the timer is automatically freed after it has fired.
- If TYPE is ATIMER_CONTINUOUS, the timer fires every TIME s/us.
+ If TYPE is ATIMER_CONTINUOUS, the timer fires every TIMESTAMP seconds.
Value is a pointer to the atimer started. It can be used in calls
to cancel_atimer; don't free it yourself. */
struct atimer *t;
sigset_t oldset;
- /* Round TIME up to the next full second if we don't have
- itimers. */
+ /* Round TIMESTAMP up to the next full second if we don't have itimers. */
#ifndef HAVE_SETITIMER
if (timestamp.tv_nsec != 0 && timestamp.tv_sec < TYPE_MAXIMUM (time_t))
timestamp = make_timespec (timestamp.tv_sec + 1, 0);
struct timespec now, interval;
#ifdef HAVE_ITIMERSPEC
- if (alarm_timer_ok)
+ if (0 <= timerfd || alarm_timer_ok)
{
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)
+# ifdef HAVE_TIMERFD
+ if (timerfd_settime (timerfd, TFD_TIMER_ABSTIME, &ispec, 0) == 0)
+ {
+ add_timer_wait_descriptor (timerfd);
+ return;
+ }
+# endif
+ if (alarm_timer_ok
+ && timer_settime (alarm_timer, TIMER_ABSTIME, &ispec, 0) == 0)
return;
}
#endif
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)
+{
+ ptrdiff_t nbytes;
+ uint64_t expirations;
+
+ eassert (fd == timerfd);
+ nbytes = emacs_read (fd, &expirations, sizeof (expirations));
+
+ if (nbytes == sizeof (expirations))
+ {
+ /* Timer should expire just once. */
+ eassert (expirations == 1);
+ do_pending_atimers ();
+ }
+ else if (nbytes < 0)
+ /* For some not yet known reason, we may get weird event and no
+ data on timer descriptor. This can break Gnus at least, see:
+ http://lists.gnu.org/archive/html/emacs-devel/2014-07/msg00503.html. */
+ eassert (errno == EAGAIN);
+ else
+ /* I don't know what else can happen with this descriptor. */
+ emacs_abort ();
+}
+
+#endif /* HAVE_TIMERFD */
/* Do pending timers. */
if (on)
set_alarm ();
else
- alarm (0);
+ {
+#ifdef HAVE_ITIMERSPEC
+ struct itimerspec ispec;
+ memset (&ispec, 0, sizeof ispec);
+ if (alarm_timer_ok)
+ timer_settime (alarm_timer, TIMER_ABSTIME, &ispec, 0);
+# ifdef HAVE_TIMERFD
+ timerfd_settime (timerfd, TFD_TIMER_ABSTIME, &ispec, 0);
+# endif
+#endif
+ 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
- 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;
+# ifdef HAVE_TIMERFD
+ /* Until this feature is considered stable, you can ask to not use it. */
+ timerfd = (egetenv ("EMACS_IGNORE_TIMERFD") ? -1 :
+ timerfd_create (CLOCK_REALTIME, TFD_NONBLOCK | TFD_CLOEXEC));
+# endif
+ if (timerfd < 0)
+ {
+ 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
free_atimers = stopped_atimers = atimers = NULL;
struct sigaction action;
emacs_sigaction_init (&action, handle_alarm_signal);
sigaction (SIGALRM, &action, 0);
+
+#ifdef ENABLE_CHECKING
+ defsubr (&Sdebug_timer_check);
+#endif
}