Hi Cong,
> I'm a newbie to libev. I wrote a TCP server with libev. My program has a
> relatively simple structure, with accept_cb, read_cb, write_cb and timeout_cb
> defined. However, when I started it, I found the accept call back is called
> right away and being called about 60K+ times per second. Each "accept()" call
> sets the errno to EINVAL, since there's no connection. The program uses more
> than 50% CPU time.
Do you properly bind the listening socket in the setupServerSocket ?
Could you reproduce the content of the setServerSocket() function ?
Also, instead of:
fcntl(svrSockFd, F_SETFL, O_NONBLOCK);
you should use:
fcntl(svrSockFd, F_SETFL, fcntl(svrSockFd, F_GETFL, 0) | O_NONBLOCK);
or even better (one less system call):
int flag = 1;
ioctl(svrSockFd, FIONBIO, &flag);
> My question is that if this is correct? Or there could be something wrong
> with my program? If this is expected, then do I need to let the accept_cb to
> sleep to avoid making the CPU too busy? But wouldn't sleeping affect the
> performance of the server?
>
> Thanks for your attention!
>
> Shawn
>
> Part of my source code:
> In main(),
> ===============
>
> int svrSockFd = setupServerSocket(SOCK_STREAM, g->m_ip, g->m_port);
>
> // Make socket non-blocking.
> fcntl(svrSockFd, F_SETFL, O_NONBLOCK);
>
> ev_io* acceptWatcher = (ev_io*)malloc(sizeof(ev_io));
>
> // Init watcher
> ev_io_init(acceptWatcher, accept_cb, svrSockFd, EV_READ);
>
> // Start watcher
> struct ev_loop* loop = EV_DEFAULT;
> ev_io_start(loop, acceptWatcher);
>
> // Wait for events to arrive
> ev_run(loop, 0);
>
> The accept_cb:
> =====================
> static void accept_cb(struct ev_loop* loop, ev_io* w, int revents)
> {
> Log::debug("serverSocket received data");
> int svrSockFd = w->fd;
>
> // accept
> sockaddr_in clientAddress;
> socklen_t sin_size = (socklen_t)sizeof(clientAddress);
> int newSockFd = accept(svrSockFd, (sockaddr *)&clientAddress,
> &sin_size);
> if (newSockFd < 0) { // -1, EAGAIN??
> if (errno == EINVAL) {
> //cout << "no connection" << endl;
> } else {
> perror("accept");
> }
> } else {
> // Handle the connection
> ...
> }
> }
Regards,
Pierre-Yves
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