iOS获取一个方法的执行时间

#import <mach/mach_time.h> // for mach_absolute_time() and friends

 

CGFloat BNRTimeBlock (void (^block)(void)) {

    mach_timebase_info_data_t info;

    if (mach_timebase_info(&info) != KERN_SUCCESS) return -1.0;

 

    uint64_t start = mach_absolute_time ();

    block ();

    uint64_t end = mach_absolute_time ();

    uint64_t elapsed = end - start;

 

    uint64_t nanos = elapsed * info.numer / info.denom;

    return (CGFloat)nanos / NSEC_PER_SEC;

 

} // BNRTimeBlock

 

 

来自：http://weblog.bignerdranch.com/316-a-timing-utility/