cds/os/posix/timer.h

   1 //$$CDS-header$$
   2
   3 #ifndef __CDS_OS_POSIX_TIMER_H
   4 #define __CDS_OS_POSIX_TIMER_H
   5
   6 #ifndef __CDS_OS_TIMER_H
   7 #   error "<cds/os/timer.h> must be included"
   8 #endif
   9
  10 #include <time.h>
  11
  12 //@cond none
  13 namespace cds { namespace OS {
  14     CDS_CXX11_INLINE_NAMESPACE namespace posix {
  15
  16         // High resolution timer
  17         // From Linux as an example
  18         class Timer {
  19         public:
  20             typedef struct timespec native_timer_type;
  21             typedef long long       native_duration_type;
  22
  23         private:
  24             native_timer_type    m_tmStart;
  25
  26         public:
  27             Timer() { current( m_tmStart ) ; }
  28
  29             static void current( native_timer_type& tmr )
  30             {
  31                 // faster than gettimeofday() and posix
  32                 clock_gettime( CLOCK_REALTIME, &tmr );
  33             }
  34
  35             static native_timer_type    current()
  36             {
  37                 native_timer_type    tmr;
  38                 current(tmr);
  39                 return tmr;
  40             }
  41
  42             double reset()
  43             {
  44                 native_timer_type ts;
  45                 current( ts );
  46                 double dblRet = ( ts.tv_sec - m_tmStart.tv_sec ) + ( ts.tv_nsec - m_tmStart.tv_nsec ) / 1.0E9;
  47                 m_tmStart = ts;
  48                 return dblRet;
  49             }
  50
  51             double duration( native_duration_type dur )
  52             {
  53                 return double( dur ) / 1.0E9;
  54             }
  55
  56             double duration()
  57             {
  58                 return duration( native_duration() );
  59             }
  60
  61             native_duration_type    native_duration()
  62             {
  63                 native_timer_type ts;
  64                 current( ts );
  65                 return native_duration( m_tmStart, ts );
  66             }
  67
  68             static native_duration_type    native_duration( const native_timer_type& nStart, const native_timer_type& nEnd )
  69             {
  70                 return native_duration_type( nEnd.tv_sec - nStart.tv_sec ) * 1000000000 + ( nEnd.tv_nsec - nStart.tv_nsec);
  71             }
  72
  73             static unsigned long long random_seed()
  74             {
  75                 native_timer_type tmr;
  76                 current( tmr );
  77                 return ( ((unsigned long long)(tmr.tv_sec)) << 32 ) + tmr.tv_nsec;
  78             }
  79         };
  80     }    // namespace posix
  81
  82 #ifndef CDS_CXX11_INLINE_NAMESPACE_SUPPORT
  83     using posix::Timer;
  84 #endif
  85
  86 }}    // namespace cds::OS
  87 //@endcond
  88
  89 #endif // #ifndef __CDS_OS_POSIX_TIMER_H