使用epoll主循环延迟执行

发布于 2024-11-29 21:00:43 字数 459 浏览 3 评论 0原文

如何使用epoll创建代码的延迟执行或超时事件？ libevent 和 libev 都有这个功能，但我不知道如何使用 epoll 来做到这一点。

目前主循环如下所示：

epoll_ctl(epfd, EPOLL_CTL_ADD, client_sock_fd, &epev);

while(1) {
    int nfds = epoll_wait(epfd, &epev, 1, 10);
    if (nfds < 0) exit(EXIT_FAILURE);
    if (nfds > 0) {
        // If an event has been recieved
    }
    // Do this every 10ms
}

我很清楚，可以通过简单地添加已经过去的时间来实现此功能，但使用 epoll 似乎是一个更干净的解决方案。

原文

How would I create a delayed execution of code or timeout events using epoll? Both libevent and libev has the functionality but I can't figure out how to do this using epoll.

Currently the main loop looks like this:

epoll_ctl(epfd, EPOLL_CTL_ADD, client_sock_fd, &epev);

while(1) {
    int nfds = epoll_wait(epfd, &epev, 1, 10);
    if (nfds < 0) exit(EXIT_FAILURE);
    if (nfds > 0) {
        // If an event has been recieved
    }
    // Do this every 10ms
}

I am well aware that this functionality could be achieved by simply adding how much time has passed but using epoll seems like a cleaner solution.

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贱人配狗天长地久 2024-12-06 21:00:43

您可以创建 timerfd 并添加epoll_wait 的文件描述符

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暮光沉寂 2024-12-06 21:00:43

愚蠢的问题：为什么不明确地记录时间呢？我在多 TCP 客户端中执行此操作（用于发送心跳），并且循环基本上执行以下操作：

uint64_t last = get_time_in_usec();
uint64_t event_interval = 10 * 1000;
while(1) {
    int nfds = epoll_wait(epfd, &epev, 1, 0); /* note that i set timeout = 0 */
    if (nfds <= 0) { /* do some cleanup logic, handle EAGAIN */
    if (nfds > 0) { /* If an event has been received */ }
    if(get_time_in_usec() >= last + event_interval) { ... }
}

get_time_in_usec 可以使用 gettimeofday 或 rdtsc 来实现linux。青年MMV

Stupid question: why not just keep track of the time explicitly? I do this in a multi-TCP client (for sending heartbeats) and the loop essentially does:

uint64_t last = get_time_in_usec();
uint64_t event_interval = 10 * 1000;
while(1) {
    int nfds = epoll_wait(epfd, &epev, 1, 0); /* note that i set timeout = 0 */
    if (nfds <= 0) { /* do some cleanup logic, handle EAGAIN */
    if (nfds > 0) { /* If an event has been received */ }
    if(get_time_in_usec() >= last + event_interval) { ... }
}

get_time_in_usec can be implemented using gettimeofday or rdtsc in linux. YMMV

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