通过 EPOLL 解决客户端同时连接多服务器的问题

项目需求是程序上同时配置了多个服务端设备

每隔一段时间需要比如1分钟连一下服务器看下是否连通

并将结果上报给平台

原来是用线程池来做的

具体大概就是定时器到了之后

遍历设备列表找到设备之后通过 socket连接发送一个指令等待服务器返回用来检查是否在线

这样的问题是如果设备不是很多的话还好但是如果有上百个设备的话

每一轮遍历需要很长时间

后来看了EPOLL尝试一下

相当于是改成单线程了但是效果不是很好

基本上还是相当于单线程测试结果感觉还是单线程在跑

后期改成协程试下看看

cpp 复制代码

bool QMCY_APP::CreateEPOLL()
{

	m_epoll_fd = epoll_create1(0);
	if (m_epoll_fd < 0)
	{
		printf("epoll_create failed\n");
		return false;
	}

	return true;
}

cpp 复制代码

bool QMCY_APP::Add2Epoll(std::shared_ptr<IQMCY>  led)
{
	int fd;
	auto ip = led->NVR_GetIP().c_str();
	auto port = led->NVR_GetPort();


	struct sockaddr_in my_addr;
	socklen_t peer_addr_size;

	

	fd = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, 0);

	if (fd == -1)
	{
		printf("Add2Epoll Create socket failed\n");
		return false;
	}

	memset(&my_addr, 0, sizeof(my_addr));
	my_addr.sin_family = AF_INET;
	my_addr.sin_addr.s_addr = inet_addr(ip);
	my_addr.sin_port = htons(port);

	int ret = connect(fd, (struct sockaddr*)&my_addr, sizeof(my_addr));

	if (ret == 0) {
		puts("connect successfully!");
		return false;
	}

	if (errno != EINPROGRESS) printf("Add2Epoll success [%s:%d] \n",ip,port);


	struct epoll_event ev;
	
	ev.events = EPOLLOUT |EPOLLET |EPOLLIN;
	ev.data.fd = fd;

	if (epoll_ctl(m_epoll_fd, EPOLL_CTL_ADD, fd, &ev) == -1)
	{
		printf("epoll_ctl failed\n");
		return false;
	}

	m_led_all.insert(std::pair<int,std::shared_ptr<IQMCY>>(fd,led));
	led->NVR_ResetState();
	return true;
}

cpp 复制代码

bool QMCY_APP::HandleEPOLL()
{
	int timeout = 3000;	
	auto index = 0;

	struct epoll_event events[MAX_EVENTS];

	while(index <m_led_all.size()*2)
	{
		int nfds = epoll_wait(m_epoll_fd, events, MAX_EVENTS, timeout);

		if (nfds < 0) {
			printf("epoll_wait\n");
		} else if (nfds == 0) {
			printf("epoll_wait timeout\n");
		} else 
		{
			for (int n = 0; n < nfds; ++n) 
			{
				printf("epoll_wait nfds:%d events:%d\n",nfds,events[n].events);		 	
				if (events[n].data.fd && (events[n].events & EPOLLOUT)) 
				{
					int connect_error = 0;
					socklen_t len = sizeof(connect_error);
					if(getsockopt(events[n].data.fd, SOL_SOCKET, SO_ERROR, (void*)(&connect_error), &len) < 0)
					{
						printf("getsockopt error\n");
						continue;
					}

					if (connect_error != 0) 
					{
						printf("fd:[%d] connect: %s\n",events[n].data.fd, strerror(connect_error));
						continue;
					}
					else
					{
						auto fd = events[n].data.fd;
						auto led = m_led_all[fd];
						printf("QMCY 00000000000000000 connect to led success [ip:%s  port:%d]\n",led->NVR_GetIP().c_str(),led->NVR_GetPort());

						struct epoll_event ev = {0};
						ev.events = EPOLLET |EPOLLIN;
						ev.data.fd = fd;
						epoll_ctl(m_epoll_fd, EPOLL_CTL_MOD, fd, &ev);

						led->NVR_ProbeOnline(fd);
					}
				}
				else if (events[n].data.fd && (events[n].events & EPOLLIN))
				{
					char buf[BUFSIZ] = {0};
					int nread,n = 0;  
					auto fd = events[n].data.fd;
					while ((nread = read(fd, buf + n, BUFSIZ-1)) > 0) {  
					    n += nread;  
						 printf("n=%d nread=%d\n",n,nread);
					}  
					if (nread == -1 && errno != EAGAIN) {  
					    perror("read error");  
						 continue;
					} 
					auto led = m_led_all[fd];

					printf("11111111Read data success [ip:%s	port:%d read=%d]\n",led->NVR_GetIP().c_str(),led->NVR_GetPort(),n);

					if(n>0)
					{
						led->NVR_ProbeAnalyse(buf,n);						
					}


				}
			}
		}
		index++;
		printf("HandleEPOLL  loop index =%d ~~~~~~~~~~~~~~~~~\n",index);
		//sleep(1);
	}

	printf("HandleEPOLL end exit ~~~~~~~~~~~~~~~~~\n");
	return true;
}

cpp 复制代码

bool QMCY_APP::DestroyEPOLL()
{
	if (m_epoll_fd > 0 ) 
	{
		close(m_epoll_fd);
	}

	return true;
}