| 1 | #include <mach/mach_time.h> |
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| 2 | #include <stdint.h> |
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| 3 | #include <stdlib.h> |
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| 4 | |
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| 5 | double intervalInCycles( uint64_t startTime, uint64_t endTime ) |
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| 6 | { |
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| 7 | uint64_t rawTime = endTime - startTime; |
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| 8 | static double conversion = 0.0; |
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| 9 | |
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| 10 | if( 0.0 == conversion ) |
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| 11 | { |
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| 12 | mach_timebase_info_data_t info; |
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| 13 | kern_return_t err = mach_timebase_info( &info ); |
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| 14 | if( 0 != err ) |
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| 15 | return 0; |
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| 16 | |
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| 17 | uint64_t freq = 0; |
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| 18 | size_t freqSize = sizeof( freq ); |
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| 19 | int err2 = sysctlbyname( "hw.cpufrequency" , &freq, &freqSize, NULL, 0L ); |
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| 20 | if( 0 != err2 ) |
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| 21 | return 0; |
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| 22 | |
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| 23 | conversion = (double) freq * (1e-9 * (double) info.numer / (double) info.denom); |
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| 24 | } |
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| 25 | |
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| 26 | return (double) rawTime * conversion; |
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| 27 | } |
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| 28 | |
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| 29 | |
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