src/gallium/auxiliary/os/os_time.h

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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 #ifndef _OS_TIME_H_
  36 #define _OS_TIME_H_
  37
  38
  39 #include "pipe/p_config.h"
  40
  41 #if defined(PIPE_OS_UNIX)
  42 #  include <unistd.h> /* usleep */
  43 #endif
  44
  45 #include "pipe/p_compiler.h"
  46
  47
  48 #ifdef __cplusplus
  49 extern "C" {
  50 #endif
  51
  52
  53 /*
  54  * Get the current time in nanoseconds from an unknown base.
  55  */
  56 int64_t
  57 os_time_get_nano(void);
  58
  59
  60 /*
  61  * Get the current time in microseconds from an unknown base.
  62  */
  63 static inline int64_t
  64 os_time_get(void)
  65 {
  66    return os_time_get_nano() / 1000;
  67 }
  68
  69
  70 /*
  71  * Sleep.
  72  */
  73 void
  74 os_time_sleep(int64_t usecs);
  75
  76
  77 /*
  78  * Helper function for detecting time outs, taking in account overflow.
  79  *
  80  * Returns true if the current time has elapsed beyond the specified interval.
  81  */
  82 static inline boolean
  83 os_time_timeout(int64_t start,
  84                 int64_t end,
  85                 int64_t curr)
  86 {
  87    if (start <= end)
  88       return !(start <= curr && curr < end);
  89    else
  90       return !((start <= curr) || (curr < end));
  91 }
  92
  93
  94 /**
  95  * Convert a relative timeout in nanoseconds into an absolute timeout,
  96  * in other words, it returns current time + timeout.
  97  * os_time_get_nano() must be monotonic.
  98  * PIPE_TIMEOUT_INFINITE is passed through unchanged. If the calculation
  99  * overflows, PIPE_TIMEOUT_INFINITE is returned.
 100  */
 101 int64_t
 102 os_time_get_absolute_timeout(uint64_t timeout);
 103
 104
 105 /**
 106  * Wait until the variable at the given memory location is zero.
 107  *
 108  * \param var           variable
 109  * \param timeout       timeout in ns, can be anything from 0 (no wait) to
 110  *                      PIPE_TIME_INFINITE (wait forever)
 111  * \return     true if the variable is zero
 112  */
 113 bool
 114 os_wait_until_zero(volatile int *var, uint64_t timeout);
 115
 116
 117 /**
 118  * Wait until the variable at the given memory location is zero.
 119  * The timeout is the absolute time when the waiting should stop. If it is
 120  * less than or equal to the current time, it only returns the status and
 121  * doesn't wait. PIPE_TIME_INFINITE waits forever. This requires that
 122  * os_time_get_nano is monotonic.
 123  *
 124  * \param var       variable
 125  * \param timeout   the time in ns when the waiting should stop
 126  * \return     true if the variable is zero
 127  */
 128 bool
 129 os_wait_until_zero_abs_timeout(volatile int *var, int64_t timeout);
 130
 131 #ifdef __cplusplus
 132 }
 133 #endif
 134
 135 #endif /* _OS_TIME_H_ */