cds/os/linux/timer.h

   1 //$$CDS-header$$
   2
   3 #ifndef __CDS_OS_LINUX_TIMER_H
   4 #define __CDS_OS_LINUX_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 //#include <sys/time.h>
  12
  13 //@cond none
  14 namespace cds { namespace OS {
  15     CDS_CXX11_INLINE_NAMESPACE namespace Linux {
  16
  17         // High resolution timer
  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
  28             Timer() { current( m_tmStart ) ; }
  29
  30             static void current( native_timer_type& tmr )
  31             {
  32                 // faster than gettimeofday() and posix
  33                 clock_gettime( CLOCK_REALTIME, &tmr );
  34             }
  35
  36             static native_timer_type    current()
  37             {
  38                 native_timer_type    tmr;
  39                 current(tmr);
  40                 return tmr;
  41             }
  42
  43             double reset()
  44             {
  45                 native_timer_type ts;
  46                 current( ts );
  47                 double dblRet = ( ts.tv_sec - m_tmStart.tv_sec ) + ( ts.tv_nsec - m_tmStart.tv_nsec ) / 1.0E9;
  48                 m_tmStart = ts;
  49                 return dblRet;
  50             }
  51
  52             double duration( native_duration_type dur )
  53             {
  54                 return double( dur ) / 1.0E9;
  55             }
  56
  57             double duration()
  58             {
  59                 return duration( native_duration() );
  60             }
  61
  62             native_duration_type    native_duration()
  63             {
  64                 native_timer_type ts;
  65                 current( ts );
  66                 return native_duration( m_tmStart, ts );
  67             }
  68
  69             static native_duration_type    native_duration( const native_timer_type& nStart, const native_timer_type& nEnd )
  70             {
  71                 return native_duration_type( nEnd.tv_sec - nStart.tv_sec ) * 1000000000 + ( nEnd.tv_nsec - nStart.tv_nsec);
  72             }
  73
  74             static unsigned long long random_seed()
  75             {
  76                 native_timer_type tmr;
  77                 current( tmr );
  78                 return ( ((unsigned long long)(tmr.tv_sec)) << 32 ) + tmr.tv_nsec;
  79             }
  80         };
  81     }    // namespace Linux
  82
  83 #ifndef CDS_CXX11_INLINE_NAMESPACE_SUPPORT
  84     typedef Linux::Timer    Timer;
  85 #endif
  86
  87 }}    // namespace cds::OS
  88 //@endcond
  89
  90 #endif // #ifndef __CDS_OS_LINUX_TIMER_H