code.delx.au - pulseaudio/blob - src/pulsecore/core-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 "core-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 / PA_NSEC_PER_USEC;
  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 <= (long) (PA_HRTIMER_THRESHOLD_USEC*PA_NSEC_PER_USEC);
  86 #endif
  87
  88     pa_assert_se(clock_getres(CLOCK_REALTIME, &ts) == 0);
  89     return ts.tv_sec == 0 && ts.tv_nsec <= (long) (PA_HRTIMER_THRESHOLD_USEC*PA_NSEC_PER_USEC);
  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 struct timeval* pa_rtclock_from_wallclock(struct timeval *tv) {
 126
 127 #ifdef HAVE_CLOCK_GETTIME
 128     struct timeval wc_now, rt_now;
 129
 130     pa_gettimeofday(&wc_now);
 131     pa_rtclock_get(&rt_now);
 132
 133     pa_assert(tv);
 134
 135     /* pa_timeval_sub() saturates on underflow! */
 136
 137     if (pa_timeval_cmp(&wc_now, tv) < 0)
 138         pa_timeval_add(&rt_now, pa_timeval_diff(tv, &wc_now));
 139     else
 140         pa_timeval_sub(&rt_now, pa_timeval_diff(&wc_now, tv));
 141
 142     *tv = rt_now;
 143 #endif
 144
 145     return tv;
 146 }
 147
 148 pa_usec_t pa_timespec_load(const struct timespec *ts) {
 149
 150     if (PA_UNLIKELY(!ts))
 151         return PA_USEC_INVALID;
 152
 153     return
 154         (pa_usec_t) ts->tv_sec * PA_USEC_PER_SEC +
 155         (pa_usec_t) ts->tv_nsec / PA_NSEC_PER_USEC;
 156 }
 157
 158 struct timespec* pa_timespec_store(struct timespec *ts, pa_usec_t v) {
 159     pa_assert(ts);
 160
 161     if (PA_UNLIKELY(v == PA_USEC_INVALID)) {
 162         ts->tv_sec = PA_INT_TYPE_MAX(time_t);
 163         ts->tv_nsec = (long) (PA_NSEC_PER_SEC-1);
 164         return NULL;
 165     }
 166
 167     ts->tv_sec = (time_t) (v / PA_USEC_PER_SEC);
 168     ts->tv_nsec = (long) ((v % PA_USEC_PER_SEC) * PA_NSEC_PER_USEC);
 169
 170     return ts;
 171 }
 172
 173 static struct timeval* wallclock_from_rtclock(struct timeval *tv) {
 174
 175 #ifdef HAVE_CLOCK_GETTIME
 176     struct timeval wc_now, rt_now;
 177
 178     pa_gettimeofday(&wc_now);
 179     pa_rtclock_get(&rt_now);
 180
 181     pa_assert(tv);
 182
 183     /* pa_timeval_sub() saturates on underflow! */
 184
 185     if (pa_timeval_cmp(&rt_now, tv) < 0)
 186         pa_timeval_add(&wc_now, pa_timeval_diff(tv, &rt_now));
 187     else
 188         pa_timeval_sub(&wc_now, pa_timeval_diff(&rt_now, tv));
 189
 190     *tv = wc_now;
 191 #endif
 192
 193     return tv;
 194 }
 195
 196 struct timeval* pa_timeval_rtstore(struct timeval *tv, pa_usec_t v, pa_bool_t rtclock) {
 197     pa_assert(tv);
 198
 199     if (v == PA_USEC_INVALID)
 200         return NULL;
 201
 202     pa_timeval_store(tv, v);
 203
 204     if (rtclock)
 205         tv->tv_usec |= PA_TIMEVAL_RTCLOCK;
 206     else
 207         wallclock_from_rtclock(tv);
 208
 209     return tv;
 210 }