服务器百万并发的原理与实现

什么是百万并发？

指的是服务器接收百万个连接或数据会在同一时刻接收到，也就是同时能看到

百万个连接或数据。

在了解服务器百万并发的同时，我们先来看看我们的百万并发服务器的结构图。

主体是以reactor为核心，链表方式存储事件以及事件对应的属性

服务端

#include 
#include 
#include 
#include 
#include 
#include 

#include 
#include 


#include 
#include 
#include 
#include                

#include 



#define BUFFER_LENGTH		1024
#define MAX_EPOLL_EVENTS	1024
#define RESOURCE_LENGTH	1024

#define SERVER_PORT			8888
#define PORT_COUNT			1

typedef int NCALLBACK(int ,int, void*);


#define HTTP_METHOD_GET		0
#define HTTP_METHOD_POST	1

struct ntyevent {
	int fd;
	int events;
	void *arg;
	int (*callback)(int fd, int events, void *arg);
	
	int status;
	char buffer[BUFFER_LENGTH];
	
	char wbuffer[BUFFER_LENGTH];
	
	int length;
	int wlength;
	//long last_active;

	// http reqeust
	int method;
	char resource[RESOURCE_LENGTH];

};

struct eventblock {
	
	struct eventblock *next;
	struct ntyevent *events;
};

struct ntyreactor {
	int epfd;
	int blkcnt;
	struct eventblock *evblks;
};


int recv_cb(int fd, int events, void *arg);
int send_cb(int fd, int events, void *arg);
struct ntyevent *ntyreactor_idx(struct ntyreactor *reactor, int sockfd);



void nty_event_set(struct ntyevent *ev, int fd, NCALLBACK callback, void *arg) {

	ev->fd = fd;
	ev->callback = callback;
	ev->events = 0;
	ev->arg = arg;
	//ev->last_active = time(NULL);

	return ;
	
}


int nty_event_add(int epfd, int events, struct ntyevent *ev) {

	struct epoll_event ep_ev = {0, {0}};
	ep_ev.data.ptr = ev;
	ep_ev.events = ev->events = events;
	
	int op;
	if (ev->status == 1) {
		op = EPOLL_CTL_MOD;
	} else {
		op = EPOLL_CTL_ADD;
		ev->status = 1;
	}
	if (epoll_ctl(epfd, op, ev->fd, &ep_ev) < 0) {
		printf("event add failed [fd=%d], events[%d]\n", ev->fd, events);
		return -1;
	}
	
	return 0;
}

int nty_event_del(int epfd, struct ntyevent *ev) 
{
	struct epoll_event ep_ev = {0, {0}};
	
	if (ev->status != 1) {
		return -1;
	}
	
	ep_ev.data.ptr = ev;
	ev->status = 0;
	epoll_ctl(epfd, EPOLL_CTL_DEL, ev->fd, &ep_ev);
	return 0;
}

// request
// location  /0voice/king/index.html HTTP/1.1
// 

int readline(char* allbuf,int idx,char* linebuf) {    
	int len = strlen(allbuf);    

	for (;idx < len; ++idx)    {        
		if(allbuf[idx]=='\r' && allbuf[idx+1]=='\n')            
			return idx+2;        
		else            
			*(linebuf++) = allbuf[idx];    
	}    

	return -1;
}


int nty_http_request(struct ntyevent *ev) {

	char linebuffer[1024] = {0};
	
	int idx = readline(ev->buffer, 0, linebuffer);
	if (strstr(linebuffer, "GET")) {
		ev->method = HTTP_METHOD_GET; //

		int i = 0;
		while(linebuffer[sizeof("GET ") + i] != ' ') i ++;
		linebuffer[sizeof("GET ") + i] = '\0';

		sprintf(ev->resource, "%s/%s", HTTP_WEB_ROOT, linebuffer+sizeof("GET "));

		//printf("resource: %s\n", ev->resource);		 //
		
	} else if (strstr(linebuffer, "POST")) {
		ev->method = HTTP_METHOD_POST;
	}
	

}

int nty_http_response_get_method(struct ntyevent *ev) {

	//int filed = open()
#if 0
	int len = sprintf(ev->wbuffer, 
	"HTTP/1.1 200 OK\r\n"
"Accept-Ranges: bytes\r\n"
"Content-Length: 78\r\n"
"Content-Type: text/html\r\n"
"Date: Sat, 06 Aug 2022 13:16:46 GMT\r\n\r\n"
"
King
");

	ev->wlength = len;
#else
	int len;
	int filefd = open(ev->resource, O_RDONLY);
	if (filefd == -1) {

		len = sprintf(ev->wbuffer, 
	"HTTP/1.1 200 OK\r\n"
"Accept-Ranges: bytes\r\n"
"Content-Length: 78\r\n"
"Content-Type: text/html\r\n"
"Date: Sat, 06 Aug 2022 13:16:46 GMT\r\n\r\n"
"
King
");

		ev->wlength = len;
	
	} else {

		struct stat stat_buf;
		fstat(filefd, &stat_buf);
		close(filefd);
#if 1
		len = sprintf(ev->wbuffer, 
	"HTTP/1.1 200 OK\r\n"
"Accept-Ranges: bytes\r\n"
"Content-Length: %ld\r\n"
"Content-Type: text/html\r\n"
"Date: Sat, 06 Aug 2022 13:16:46 GMT\r\n\r\n", stat_buf.st_size);
#else
len = sprintf(ev->wbuffer, 
	"HTTP/1.1 200 OK\r\n"
"Accept-Ranges: bytes\r\n"
"Content-Length: %ld\r\n"
"Content-Type: image/png\r\n"
"Date: Sat, 06 Aug 2022 13:16:46 GMT\r\n\r\n", stat_buf.st_size);


#endif
		ev->wlength = len;

	}

#endif
	return len;
}


int nty_http_response(struct ntyevent *ev) {

	// ev->method, ev->resouces

	if (ev->method == HTTP_METHOD_GET) {
		return nty_http_response_get_method(ev);
	} else if (ev->method == HTTP_METHOD_POST) {

	}
	

}


// connection
// sock_item --> fd, rbuffer, wbuffer, clientaddr
int recv_cb(int fd, int events, void *arg) {

	struct ntyreactor *reactor = (struct ntyreactor*)arg;
	struct ntyevent *ev = ntyreactor_idx(reactor, fd);

	if (ev == NULL) return -1;
	//
	int len = recv(fd, ev->buffer, BUFFER_LENGTH, 0);
	nty_event_del(reactor->epfd, ev);

	if (len > 0) {
		
		ev->length = len;
		ev->buffer[len] = '\0';

		//printf("recv [%d]:%s\n", fd, ev->buffer);

		nty_http_request(ev); // parser http hdr

		nty_event_set(ev, fd, send_cb, reactor);
		nty_event_add(reactor->epfd, EPOLLOUT, ev);
		
		
	} else if (len == 0) {

		nty_event_del(reactor->epfd, ev);
		//printf("recv_cb --> disconnect\n");
		close(ev->fd);
		 
	} else {

		if (errno == EAGAIN && errno == EWOULDBLOCK) { //
			
		} else if (errno == ECONNRESET){
			nty_event_del(reactor->epfd, ev);
			close(ev->fd);
		}
		//printf("recv[fd=%d] error[%d]:%s\n", fd, errno, strerror(errno));
		
	}

	return len;
}


int send_cb(int fd, int events, void *arg) {

	struct ntyreactor *reactor = (struct ntyreactor*)arg;
	struct ntyevent *ev = ntyreactor_idx(reactor, fd);

	if (ev == NULL) return -1;

	nty_http_response(ev); //encode

	int len = send(fd, ev->wbuffer, ev->wlength, 0);
	if (len > 0) {
		//printf("resource: %s\n", ev->resource);

		int filefd = open(ev->resource, O_RDONLY);
		//if (filefd < 0) return -1;
		
		struct stat stat_buf;
		fstat(filefd, &stat_buf);
		
		int flag = fcntl(fd, F_GETFL, 0);
		flag &= ~O_NONBLOCK;
		fcntl(fd, F_SETFL, flag);
			
		int ret = sendfile(fd, filefd, NULL, stat_buf.st_size);
		if (ret == -1) {
			printf("sendfile: errno: %d\n", errno);
		}

		flag |= O_NONBLOCK;
		fcntl(fd, F_SETFL, flag);

		close(filefd);

		send(fd, "\r\n", 2, 0);

		nty_event_del(reactor->epfd, ev);
		nty_event_set(ev, fd, recv_cb, reactor);
		nty_event_add(reactor->epfd, EPOLLIN, ev);
		
	} else {

		nty_event_del(reactor->epfd, ev);
		close(ev->fd);

		//printf("send[fd=%d] error %s\n", fd, strerror(errno));

	}

	return len;
}

int curfds = 0;

#define TIME_SUB_MS(tv1, tv2)  ((tv1.tv_sec - tv2.tv_sec) * 1000 + (tv1.tv_usec - tv2.tv_usec) / 1000)

struct timeval tv_begin;

int accept_cb(int fd, int events, void *arg) {

	struct ntyreactor *reactor = (struct ntyreactor*)arg;
	if (reactor == NULL) return -1;

	struct sockaddr_in client_addr;
	socklen_t len = sizeof(client_addr);

	int clientfd;

	if ((clientfd = accept(fd, (struct sockaddr*)&client_addr, &len)) == -1) {
		if (errno != EAGAIN && errno != EINTR) {
			
		}
		printf("accept: %s\n", strerror(errno));
		return -1;
	}

	
	int flag = 0;
	if ((flag = fcntl(clientfd, F_SETFL, O_NONBLOCK)) < 0) {
		printf("%s: fcntl nonblocking failed, %d\n", __func__, MAX_EPOLL_EVENTS);
		return -1;
	}

	struct ntyevent *event = ntyreactor_idx(reactor, clientfd);

	if (event == NULL) return -1;
		
	nty_event_set(event, clientfd, recv_cb, reactor);
	nty_event_add(reactor->epfd, EPOLLIN, event);

	if (curfds++ % 1000 == 999) {
		struct timeval tv_cur;
		memcpy(&tv_cur, &tv_begin, sizeof(struct timeval));
		
		gettimeofday(&tv_begin, NULL);

		int time_used = TIME_SUB_MS(tv_begin, tv_cur);
		printf("connections: %d, sockfd:%d, time_used:%d\n", curfds, clientfd, time_used);
	}

	//printf("new connect [%s:%d], pos[%d]\n", 
	//	inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port), clientfd);

	return 0;

}

int init_sock(short port) {

	int fd = socket(AF_INET, SOCK_STREAM, 0);
	fcntl(fd, F_SETFL, O_NONBLOCK);

	struct sockaddr_in server_addr;
	memset(&server_addr, 0, sizeof(server_addr));
	server_addr.sin_family = AF_INET;
	server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
	server_addr.sin_port = htons(port);

	        if (bind(fd, (struct sockaddr*)&addr, sizeof(struct sockaddr_in)) < 0) {
	            perror("bind");
	            return 2;
	        }

	if (listen(fd, 20) < 0) {
		printf("listen failed : %s\n", strerror(errno));
		return -1;
	}

	printf("listen server port : %d\n", port);
	gettimeofday(&tv_begin, NULL);

	return fd;
}


int ntyreactor_alloc(struct ntyreactor *reactor) {

	if (reactor == NULL) return -1;
	if (reactor->evblks == NULL) return -1;
	
	struct eventblock *blk = reactor->evblks;

	while (blk->next != NULL) {
		blk = blk->next;
	}

	struct ntyevent* evs = (struct ntyevent*)malloc((MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));
	if (evs == NULL) {
		printf("ntyreactor_alloc ntyevent failed\n");
		return -2;
	}
	memset(evs, 0, (MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));

	struct eventblock *block = malloc(sizeof(struct eventblock));
	if (block == NULL) {
		printf("ntyreactor_alloc eventblock failed\n");
		return -3;
	}
	block->events = evs;
	block->next = NULL;

	blk->next = block;
	reactor->blkcnt ++;

	return 0;
}

struct ntyevent *ntyreactor_idx(struct ntyreactor *reactor, int sockfd) {

	if (reactor == NULL) return NULL;
	if (reactor->evblks == NULL) return NULL;

	int blkidx = sockfd / MAX_EPOLL_EVENTS;
	while (blkidx >= reactor->blkcnt) {
		ntyreactor_alloc(reactor);
	}

	int i = 0;
	struct eventblock *blk = reactor->evblks;
	while (i++ != blkidx && blk != NULL) {
		blk = blk->next;
	}

	return &blk->events[sockfd % MAX_EPOLL_EVENTS];
}


int ntyreactor_init(struct ntyreactor *reactor) {

	if (reactor == NULL) return -1;
	memset(reactor, 0, sizeof(struct ntyreactor));

	reactor->epfd = epoll_create(1);
	if (reactor->epfd <= 0) {
		printf("create epfd in %s err %s\n", __func__, strerror(errno));
		return -2;
	}

	struct ntyevent* evs = (struct ntyevent*)malloc((MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));
	if (evs == NULL) {
		printf("create epfd in %s err %s\n", __func__, strerror(errno));
		close(reactor->epfd);
		return -3;
	}
	memset(evs, 0, (MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));

	struct eventblock *block = malloc(sizeof(struct eventblock));
	if (block == NULL) {
		free(evs);
		close(reactor->epfd);
		return -3;
	}
	block->events = evs;
	block->next = NULL;

	reactor->evblks = block;
	reactor->blkcnt = 1;

	return 0;
}

int ntyreactor_destory(struct ntyreactor *reactor) {

	close(reactor->epfd);

	struct eventblock *blk = reactor->evblks;
	struct eventblock *blk_next;
	while (blk != NULL) {
		blk_next = blk->next;

		free(blk->events);
		free(blk);
		
		blk = blk_next;
	}

	return 0;
}



int ntyreactor_addlistener(struct ntyreactor *reactor, int sockfd, NCALLBACK *acceptor) {

	if (reactor == NULL) return -1;
	if (reactor->evblks == NULL) return -1;

	struct ntyevent *event = ntyreactor_idx(reactor, sockfd);
	if (event == NULL) return -1;

	nty_event_set(event, sockfd, acceptor, reactor);
	nty_event_add(reactor->epfd, EPOLLIN, event);

	return 0;
}



int ntyreactor_run(struct ntyreactor *reactor) {
	if (reactor == NULL) return -1;
	if (reactor->epfd < 0) return -1;
	if (reactor->evblks == NULL) return -1;
	
	struct epoll_event events[MAX_EPOLL_EVENTS+1];
	
	int checkpos = 0, i;

	while (1) {

		int nready = epoll_wait(reactor->epfd, events, MAX_EPOLL_EVENTS, 1000);
		if (nready < 0) {
			printf("epoll_wait error, exit\n");
			continue;
		}

		for (i = 0;i < nready;i ++) {

			struct ntyevent *ev = (struct ntyevent*)events[i].data.ptr;

			if ((events[i].events & EPOLLIN) && (ev->events & EPOLLIN)) {
				ev->callback(ev->fd, events[i].events, ev->arg);
			}
			if ((events[i].events & EPOLLOUT) && (ev->events & EPOLLOUT)) {
				ev->callback(ev->fd, events[i].events, ev->arg);
			}
			
		}

	}
}

int main(int argc, char *argv[]) {

	
	struct ntyreactor *reactor = (struct ntyreactor*)malloc(sizeof(struct ntyreactor));
	ntyreactor_init(reactor);

	unsigned short port = SERVER_PORT;
	if (argc == 2) {
		port = atoi(argv[1]);
	}

	int i = 0;
	int sockfds[PORT_COUNT] = {0};
	
	for (i = 0;i < PORT_COUNT;i ++) {
		sockfds[i] = init_sock(port+i);
		ntyreactor_addlistener(reactor, sockfds[i], accept_cb);
	}


	ntyreactor_run(reactor);

	ntyreactor_destory(reactor);
	
	for (i = 0;i < PORT_COUNT;i ++) {
		close(sockfds[i]);
	}
	free(reactor);
	

	return 0;
}

客户端(向服务器一直发请求)

#include 
#include 
#include 

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 


#define MAX_BUFFER		128
#define MAX_EPOLLSIZE	(384*1024)
#define MAX_PORT		100

#define TIME_SUB_MS(tv1, tv2)  ((tv1.tv_sec - tv2.tv_sec) * 1000 + (tv1.tv_usec - tv2.tv_usec) / 1000)

int isContinue = 0;

static int ntySetNonblock(int fd) {
	int flags;

	flags = fcntl(fd, F_GETFL, 0);
	if (flags < 0) return flags;
	flags |= O_NONBLOCK;
	if (fcntl(fd, F_SETFL, flags) < 0) return -1;
	return 0;
}

static int ntySetReUseAddr(int fd) {
	int reuse = 1;
	return setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *)&reuse, sizeof(reuse));
}



int main(int argc, char **argv) {
	if (argc <= 2) {
		printf("Usage: %s ip port\n", argv[0]);
		exit(0);
	}

	const char *ip = argv[1];
	int port = atoi(argv[2]);
	int connections = 0;
	char buffer[128] = {0};
	int i = 0, index = 0;

	struct epoll_event events[MAX_EPOLLSIZE];
	
	int epoll_fd = epoll_create(MAX_EPOLLSIZE);
	
	strcpy(buffer, " Data From MulClient\n");
		
	struct sockaddr_in addr;
	memset(&addr, 0, sizeof(struct sockaddr_in));
	
	addr.sin_family = AF_INET;
	addr.sin_addr.s_addr = inet_addr(ip);

	struct timeval tv_begin;
	gettimeofday(&tv_begin, NULL);

	while (1) {
		if (++index >= MAX_PORT) index = 0;
		
		struct epoll_event ev;
		int sockfd = 0;

		if (connections < 340000 && !isContinue) {
			sockfd = socket(AF_INET, SOCK_STREAM, 0);
			if (sockfd == -1) {
				perror("socket");
				goto err;
			}

			//ntySetReUseAddr(sockfd);
			addr.sin_port = htons(port+index);

			if (connect(sockfd, (struct sockaddr*)&addr, sizeof(struct sockaddr_in)) < 0) {
				perror("connect");
				goto err;
			}
			ntySetNonblock(sockfd);
			ntySetReUseAddr(sockfd);

			sprintf(buffer, "Hello Server: client --> %d\n", connections);
			send(sockfd, buffer, strlen(buffer), 0);

			ev.data.fd = sockfd;
			ev.events = EPOLLIN | EPOLLOUT;
			epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sockfd, &ev);
		
			connections ++;
		}
		//connections ++;
		if (connections % 1000 == 999 || connections >= 340000) {
			struct timeval tv_cur;
			memcpy(&tv_cur, &tv_begin, sizeof(struct timeval));
			
			gettimeofday(&tv_begin, NULL);

			int time_used = TIME_SUB_MS(tv_begin, tv_cur);
			printf("connections: %d, sockfd:%d, time_used:%d\n", connections, sockfd, time_used);

			int nfds = epoll_wait(epoll_fd, events, connections, 100);
			for (i = 0;i < nfds;i ++) {
				int clientfd = events[i].data.fd;

				if (events[i].events & EPOLLOUT) {
					sprintf(buffer, "data from %d\n", clientfd);
					send(sockfd, buffer, strlen(buffer), 0);
				} else if (events[i].events & EPOLLIN) {
					char rBuffer[MAX_BUFFER] = {0};				
					ssize_t length = recv(sockfd, rBuffer, MAX_BUFFER, 0);
					if (length > 0) {
						printf(" RecvBuffer:%s\n", rBuffer);

						if (!strcmp(rBuffer, "quit")) {
							isContinue = 0;
						}
						
					} else if (length == 0) {
						printf(" Disconnect clientfd:%d\n", clientfd);
						connections --;
						close(clientfd);
					} else {
						if (errno == EINTR) continue;

						printf(" Error clientfd:%d, errno:%d\n", clientfd, errno);
						close(clientfd);
					}
				} else {
					printf(" clientfd:%d, errno:%d\n", clientfd, errno);
					close(clientfd);
				}
			}
		}

		usleep(500);
	}

	return 0;

err:
	printf("error : %s\n", strerror(errno));
	return 0;
	
}

实现效果跟服务器的性能和台数也有关系，我只有一台服务器并且内存很小只有1G，所以到不了百万并发，多几台服务器就可以实现百万并发了

还有一个细节就是在测试百万并发的时候，尽量减少IO操作提升百万并发效率