如何准确计算在iPhone上调用功能所需的时间？ [英] How do I accurately time how long it takes to call a function on the iPhone?

问题描述

我想知道将消息发送到具有至少1ms准确度的对象需要多长时间。我该怎么办？

I would like to know how long it's taking to send a message to an object with at least a 1ms accuracy. How do I do this?

推荐答案

您可以使用 mach_absolute_time 来衡量以纳秒为单位。

You can use mach_absolute_time to measure in nanoseconds.

#import <mach/mach_time.h>

uint64_t startTime = 0;
uint64_t endTime = 0;
uint64_t elapsedTime = 0;
uint64_t elapsedTimeNano = 0;

mach_timebase_info_data_t timeBaseInfo;
mach_timebase_info(&timeBaseInfo);

startTime = mach_absolute_time();

//do something here

endTime = mach_absolute_time();

elapsedTime = endTime - startTime;
elapsedTimeNano = elapsedTime * timeBaseInfo.numer / timeBaseInfo.denom;

参考：
技术Q& A QA1398：马赫绝对时间单位

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