code.delx.au - pulseaudio/blob - src/pulsecore/rtclock.c

   1 /***
   2   This file is part of PulseAudio.
   3
   4   Copyright 2004-2006 Lennart Poettering
   5   Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
   6
   7   PulseAudio is free software; you can redistribute it and/or modify
   8   it under the terms of the GNU Lesser General Public License as
   9   published by the Free Software Foundation; either version 2.1 of the
  10   License, or (at your option) any later version.
  11
  12   PulseAudio is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15   Lesser General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General Public
  18   License along with PulseAudio; if not, write to the Free Software
  19   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  20   USA.
  21 ***/
  22
  23 #ifdef HAVE_CONFIG_H
  24 #include <config.h>
  25 #endif
  26
  27 #include <stddef.h>
  28 #include <time.h>
  29 #include <sys/time.h>
  30 #include <errno.h>
  31
  32 #ifdef HAVE_SYS_PRCTL_H
  33 #include <sys/prctl.h>
  34 #endif
  35
  36 #include <pulse/timeval.h>
  37 #include <pulsecore/macro.h>
  38 #include <pulsecore/core-error.h>
  39
  40 #include "rtclock.h"
  41
  42 pa_usec_t pa_rtclock_age(const struct timeval *tv) {
  43     struct timeval now;
  44     pa_assert(tv);
  45
  46     return pa_timeval_diff(pa_rtclock_get(&now), tv);
  47 }
  48
  49 struct timeval *pa_rtclock_get(struct timeval *tv) {
  50 #ifdef HAVE_CLOCK_GETTIME
  51     struct timespec ts;
  52
  53 #ifdef CLOCK_MONOTONIC
  54     /* No locking or atomic ops for no_monotonic here */
  55     static pa_bool_t no_monotonic = FALSE;
  56
  57     if (!no_monotonic)
  58         if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0)
  59             no_monotonic = TRUE;
  60
  61     if (no_monotonic)
  62 #endif
  63         pa_assert_se(clock_gettime(CLOCK_REALTIME, &ts) == 0);
  64
  65     pa_assert(tv);
  66
  67     tv->tv_sec = ts.tv_sec;
  68     tv->tv_usec = ts.tv_nsec / 1000;
  69
  70     return tv;
  71
  72 #else /* HAVE_CLOCK_GETTIME */
  73
  74     return pa_gettimeofday(tv);
  75
  76 #endif
  77 }
  78
  79 pa_bool_t pa_rtclock_hrtimer(void) {
  80 #ifdef HAVE_CLOCK_GETTIME
  81     struct timespec ts;
  82
  83 #ifdef CLOCK_MONOTONIC
  84     if (clock_getres(CLOCK_MONOTONIC, &ts) >= 0)
  85         return ts.tv_sec == 0 && ts.tv_nsec <= PA_HRTIMER_THRESHOLD_USEC*1000;
  86 #endif
  87
  88     pa_assert_se(clock_getres(CLOCK_REALTIME, &ts) == 0);
  89     return ts.tv_sec == 0 && ts.tv_nsec <= PA_HRTIMER_THRESHOLD_USEC*1000;
  90
  91 #else /* HAVE_CLOCK_GETTIME */
  92
  93     return FALSE;
  94
  95 #endif
  96 }
  97
  98 #define TIMER_SLACK_NS (int) ((500 * PA_NSEC_PER_USEC))
  99
 100 void pa_rtclock_hrtimer_enable(void) {
 101 #ifdef PR_SET_TIMERSLACK
 102     int slack_ns;
 103
 104     if ((slack_ns = prctl(PR_GET_TIMERSLACK, 0, 0, 0, 0)) < 0) {
 105         pa_log_info("PR_GET_TIMERSLACK/PR_SET_TIMERSLACK not supported.");
 106         return;
 107     }
 108
 109     pa_log_debug("Timer slack is set to %i us.", (int) (slack_ns/PA_NSEC_PER_USEC));
 110
 111     if (slack_ns > TIMER_SLACK_NS) {
 112         slack_ns = TIMER_SLACK_NS;
 113
 114         pa_log_debug("Setting timer slack to %i us.", (int) (slack_ns/PA_NSEC_PER_USEC));
 115
 116         if (prctl(PR_SET_TIMERSLACK, slack_ns, 0, 0, 0) < 0) {
 117             pa_log_warn("PR_SET_TIMERSLACK failed: %s", pa_cstrerror(errno));
 118             return;
 119         }
 120     }
 121
 122 #endif
 123 }
 124
 125 pa_usec_t pa_rtclock_now(void) {
 126     struct timeval tv;
 127
 128     return pa_timeval_load(pa_rtclock_get(&tv));
 129 }
 130
 131 struct timeval* pa_rtclock_from_wallclock(struct timeval *tv) {
 132
 133 #ifdef HAVE_CLOCK_GETTIME
 134     struct timeval wc_now, rt_now;
 135
 136     pa_gettimeofday(&wc_now);
 137     pa_rtclock_get(&rt_now);
 138
 139     pa_assert(tv);
 140
 141     if (pa_timeval_cmp(&wc_now, tv) < 0)
 142         pa_timeval_add(&rt_now, pa_timeval_diff(tv, &wc_now));
 143     else
 144         pa_timeval_sub(&rt_now, pa_timeval_diff(&wc_now, tv));
 145
 146     *tv = rt_now;
 147 #endif
 148
 149     return tv;
 150 }
 151
 152 pa_usec_t pa_timespec_load(const struct timespec *ts) {
 153     pa_assert(ts);
 154
 155     return
 156         (pa_usec_t) ts->tv_sec * PA_USEC_PER_SEC +
 157         (pa_usec_t) ts->tv_nsec / PA_NSEC_PER_USEC;
 158 }