c++ 异步编程

背景

须要提升工程运行效率，将里面多个环节进行同步处理。可是在网上找了几个demo以后，发现调用复杂的库（future等）和模块用到的库可能存在潜在的冲突，结果future好像和tensorRT冲突，thread好像和openGL冲突。存在一些问题。试来试去，仍是最简单的thread比较好使，openGL的问题留给之后解决吧。

代码

//g++ -o mu test.cpp -std=c++11 -lpthread

#include <iostream>
#include <string>
#include <unistd.h>
#include <vector>
#include <thread>
#include"time.h"

class xx {
private:
    int s, n;
public:

    std::vector<int> out;
    std::vector<bool> status;
    int dd;

    /*用两个元素的vector实现轮询的处理*/
    xx() {
        s = 0, n = 0, dd = 0;
        for (int i = 0; i < 2; i++) {
            out.push_back(0);
            status.push_back(false);
        }
        std::cout << "dd: " << dd << ";" << std::endl;

    }

    /*运行时间4ms起，用它表示主代码耗时*/
    void get() {
        n = (n + 1) % 2;
        dd = out[n];
        out[n] = 0;
        status[n] = false;
        std::cout << "s:" << s << " ;dd: " << dd << " ;n: " << n << ";" << std::endl;
        usleep(4000);//4 ms
    }

    /*能够插入时提醒*/
    bool check() {
        int nn = s;
        for (int i = 0; i < 2; i++) {
            if (!status[nn]) {
                return true;
            }
            nn = (nn + 1) % 2;
        }
        return false;
    }

    /*6ms，用它表示前处理*/
    void run() {
        usleep(6000);//6 ms
        int nn = (s + 1) % 2;
        if (!status[nn]) {
            s = (s + 1) % 2;
            out[s] = 5;
            status[s] = 1;
        } else {
            printf("pass is %d", s);
        }
    }
};

/*linux没有此函数，这是网上别人加了个壳实现的*/
unsigned long GetTickCount() {
    // https://blog.csdn.net/guang11cheng/article/details/6865992
    struct timespec ts;
    clock_gettime(CLOCK_MONOTONIC, &ts);
    return (ts.tv_sec * 1000 + ts.tv_nsec / 1000000);
}

int main() {
    xx *yy = new xx();
    float ms = 0;
    int N = 100;
    /*顺序执行耗时*/
    unsigned long t1 = GetTickCount();
    for (int i = 0; i < N; i++) {
        yy->run();
        yy->get();
    }
    unsigned long t2 = GetTickCount();
    std::cout << "ordering excute eclipse: " << t2 - t1 << "ms\n";
    /*lambda函数*/
    auto detectionReprocess = [&]() {
        yy->run();
    };

    /*异步执行耗时*/
    t1 = GetTickCount();
    std::thread dataPreparation(detectionReprocess);
    for (int i = 0; i < N; i++) {
        dataPreparation.join();
        dataPreparation = std::thread(detectionReprocess);
        yy->get();
    }
    t2 = GetTickCount();
    std::cout << "threading eclipse: " << t2 - t1 << "ms\n";
    /*最后新建的thread须要join，不然报错*/
    dataPreparation.join();
    yy->get();
}

耗时

ordering excute eclipse: 1083ms
threading eclipse: 659ms