[C++知识库]c++延时函数精度问题

任务：假设需要做视频编解码显示，需要频繁调用sleep(10ms)函数，如果sleep函数内部误差过大，会导致fps不准确，特别是需要高fps任务。
对比几个方法，测试误差。

#include <iostream>
#include <thread>
#include <chrono>
#include <sys/time.h>

void sleep_for(double ms)
{
    // 单位粒度越小，时间越准确，CPU资源占用相对升高
    // std::chrono::milliseconds MinSleepDuration(1);   //毫秒
    std::chrono::microseconds MinSleepDuration(100); //微秒
    // std::chrono::nanoseconds MinSleepDuration(100);  //纳秒

    std::chrono::high_resolution_clock::time_point start = std::chrono::high_resolution_clock::now();
    while (std::chrono::duration<double>(std::chrono::high_resolution_clock::now() - start).count() * 1000 < ms)
    {
        std::this_thread::sleep_for(MinSleepDuration);
    }
}

int main()
{
    // 模拟100fps
    int fps = 0;
    std::chrono::milliseconds dura(10); // 10ms

    std::chrono::high_resolution_clock::time_point tnow = std::chrono::high_resolution_clock::now();
    for (int i = 0; i < 1000; ++i)
    {
        std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }

    std::chrono::high_resolution_clock::time_point tpost = std::chrono::high_resolution_clock::now();
    std::cout << std::chrono::duration_cast<std::chrono::duration<double>>(tpost - tnow).count() * 1000 << std::endl;

    tnow = std::chrono::high_resolution_clock::now();
    for (int i = 0; i < 1000; ++i)
    {
        sleep_for(10);
    }

    tpost = std::chrono::high_resolution_clock::now();
    std::cout << std::chrono::duration_cast<std::chrono::duration<double>>(tpost - tnow).count() * 1000 << std::endl;

    return 0;
}