29 lines
654 B
C
29 lines
654 B
C
|
#include <mach/mach_time.h>
|
||
|
|
#include <stdint.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
|
||
|
|
double intervalInCycles( uint64_t startTime, uint64_t endTime )
|
||
|
|
{
|
||
|
|
uint64_t rawTime = endTime - startTime;
|
||
|
|
static double conversion = 0.0;
|
||
|
|
|
||
|
|
if( 0.0 == conversion )
|
||
|
|
{
|
||
|
|
mach_timebase_info_data_t info;
|
||
|
|
kern_return_t err = mach_timebase_info( &info );
|
||
|
|
if( 0 != err )
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
uint64_t freq = 0;
|
||
|
|
size_t freqSize = sizeof( freq );
|
||
|
|
int err2 = sysctlbyname( "hw.cpufrequency", &freq, &freqSize, NULL, 0L );
|
||
|
|
if( 0 != err2 )
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
conversion = (double) freq * (1e-9 * (double) info.numer / (double) info.denom);
|
||
|
|
}
|
||
|
|
|
||
|
|
return (double) rawTime * conversion;
|
||
|
|
}
|
||
|
|
|