时间代码块的调试

#import// for mach_absolute_time

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;

}

uint64_t begin = mach_absolute_time();

[self doSomething];

uint64_t end = mach_absolute_time();

NSLog(@"Time %g s", MachTimeToSecs(end - begin));