src/util/os_time.c

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  27
  28 /**
  29  * @file
  30  * OS independent time-manipulation functions.
  31  *
  32  * @author Jose Fonseca <jfonseca@vmware.com>
  33  */
  34
  35 #include "os_time.h"
  36
  37 /* TODO: fix this dependency */
  38 #include "gallium/include/pipe/p_config.h"
  39
  40 #include "util/u_atomic.h"
  41
  42 #if defined(PIPE_OS_UNIX)
  43 #  include <time.h> /* timeval */
  44 #  include <sys/time.h> /* timeval */
  45 #  include <sched.h> /* sched_yield */
  46 #  include <errno.h>
  47 #elif defined(PIPE_SUBSYSTEM_WINDOWS_USER)
  48 #  include <windows.h>
  49 #else
  50 #  error Unsupported OS
  51 #endif
  52
  53
  54 int64_t
  55 os_time_get_nano(void)
  56 {
  57 #if defined(PIPE_OS_LINUX)
  58
  59    struct timespec tv;
  60    clock_gettime(CLOCK_MONOTONIC, &tv);
  61    return tv.tv_nsec + tv.tv_sec*INT64_C(1000000000);
  62
  63 #elif defined(PIPE_OS_UNIX)
  64
  65    struct timeval tv;
  66    gettimeofday(&tv, NULL);
  67    return tv.tv_usec*INT64_C(1000) + tv.tv_sec*INT64_C(1000000000);
  68
  69 #elif defined(PIPE_SUBSYSTEM_WINDOWS_USER)
  70
  71    static LARGE_INTEGER frequency;
  72    LARGE_INTEGER counter;
  73    int64_t secs, nanosecs;
  74    if(!frequency.QuadPart)
  75       QueryPerformanceFrequency(&frequency);
  76    QueryPerformanceCounter(&counter);
  77    /* Compute seconds and nanoseconds parts separately to
  78     * reduce severity of precision loss.
  79     */
  80    secs = counter.QuadPart / frequency.QuadPart;
  81    nanosecs = (counter.QuadPart % frequency.QuadPart) * INT64_C(1000000000)
  82       / frequency.QuadPart;
  83    return secs*INT64_C(1000000000) + nanosecs;
  84
  85 #else
  86
  87 #error Unsupported OS
  88
  89 #endif
  90 }
  91
  92
  93
  94 void
  95 os_time_sleep(int64_t usecs)
  96 {
  97 #if defined(PIPE_OS_LINUX)
  98    struct timespec time;
  99    time.tv_sec = usecs / 1000000;
 100    time.tv_nsec = (usecs % 1000000) * 1000;
 101    while (clock_nanosleep(CLOCK_MONOTONIC, 0, &time, &time) == EINTR);
 102
 103 #elif defined(PIPE_OS_UNIX)
 104    usleep(usecs);
 105
 106 #elif defined(PIPE_SUBSYSTEM_WINDOWS_USER)
 107    DWORD dwMilliseconds = (DWORD) ((usecs + 999) / 1000);
 108    /* Avoid Sleep(O) as that would cause to sleep for an undetermined duration */
 109    if (dwMilliseconds) {
 110       Sleep(dwMilliseconds);
 111    }
 112 #else
 113 #  error Unsupported OS
 114 #endif
 115 }
 116
 117
 118
 119 int64_t
 120 os_time_get_absolute_timeout(uint64_t timeout)
 121 {
 122    int64_t time, abs_timeout;
 123
 124    /* Also check for the type upper bound. */
 125    if (timeout == OS_TIMEOUT_INFINITE || timeout > INT64_MAX)
 126       return OS_TIMEOUT_INFINITE;
 127
 128    time = os_time_get_nano();
 129    abs_timeout = time + (int64_t)timeout;
 130
 131    /* Check for overflow. */
 132    if (abs_timeout < time)
 133       return OS_TIMEOUT_INFINITE;
 134
 135    return abs_timeout;
 136 }
 137
 138
 139 bool
 140 os_wait_until_zero(volatile int *var, uint64_t timeout)
 141 {
 142    if (!p_atomic_read(var))
 143       return true;
 144
 145    if (!timeout)
 146       return false;
 147
 148    if (timeout == OS_TIMEOUT_INFINITE) {
 149       while (p_atomic_read(var)) {
 150 #if defined(PIPE_OS_UNIX)
 151          sched_yield();
 152 #endif
 153       }
 154       return true;
 155    }
 156    else {
 157       int64_t start_time = os_time_get_nano();
 158       int64_t end_time = start_time + timeout;
 159
 160       while (p_atomic_read(var)) {
 161          if (os_time_timeout(start_time, end_time, os_time_get_nano()))
 162             return false;
 163
 164 #if defined(PIPE_OS_UNIX)
 165          sched_yield();
 166 #endif
 167       }
 168       return true;
 169    }
 170 }
 171
 172
 173 bool
 174 os_wait_until_zero_abs_timeout(volatile int *var, int64_t timeout)
 175 {
 176    if (!p_atomic_read(var))
 177       return true;
 178
 179    if (timeout == OS_TIMEOUT_INFINITE)
 180       return os_wait_until_zero(var, OS_TIMEOUT_INFINITE);
 181
 182    while (p_atomic_read(var)) {
 183       if (os_time_get_nano() >= timeout)
 184          return false;
 185
 186 #if defined(PIPE_OS_UNIX)
 187       sched_yield();
 188 #endif
 189    }
 190    return true;
 191 }