mach_absolute_time 快速容易的方法来检测一段ios 代码执行的效率函数

#import <mach/mach_time.h>

double MachTimeToSecs(uint64_t time)
{
mach_timebase_info_data_t timebase;
mach_timebase_info(&timebase);
return (double)time * (double)timebase.numer /
(double)timebase.denom /1e9;
}

- (void)profileDoSomething
{
uint64_t begin = mach_absolute_time();
[doSomething];
uint64_t end = mach_absolute_time();
NSLog(@"Time taken to doSomething %g s",
MachTimeToSecs(end - begin));
}