Linux select实现socket单线程多路复用
大约 4 分钟
Linux select实现socket单线程多路复用
select版本比阻塞版本的性能起码高了3倍+
# select版本
dhb@dev:~/下载/webbench-1.5$ webbench -c 1000 -t 30 http://127.0.0.1:1500/t
Webbench - Simple Web Benchmark 1.5
Copyright (c) Radim Kolar 1997-2004, GPL Open Source Software.
Benchmarking: GET http://127.0.0.1:1500/t
1000 clients, running 30 sec.
Speed=735248 pages/min, 269580 bytes/sec.
Requests: 367610 susceed, 14 failed.
# 阻塞版本
dhb@dev:~/下载/webbench-1.5$ webbench -c 1000 -t 30 http://127.0.0.1:1500/t
Webbench - Simple Web Benchmark 1.5
Copyright (c) Radim Kolar 1997-2004, GPL Open Source Software.
Benchmarking: GET http://127.0.0.1:1500/t
1000 clients, running 30 sec.
Speed=261244 pages/min, 95729 bytes/sec.
Requests: 130540 susceed, 82 failed.
代码
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netinet/in.h>
using namespace std;
#define BUFFER_SIZE 512
#define SEND_STR "HTTP/1.1 200 OK\r\n\r\nok"
#define BACKLOG 5
int get_line(int, char *, int);
int create_listen(int);
void handler(int, char *, char *);
/**********************************************************************/
/* Get a line from a socket, whether the line ends in a newline,
* carriage return, or a CRLF combination. Terminates the string read
* with a null character. If no newline indicator is found before the
* end of the buffer, the string is terminated with a null. If any of
* the above three line terminators is read, the last character of the
* string will be a linefeed and the string will be terminated with a
* null character.
* Parameters: the socket descriptor
* the buffer to save the data in
* the size of the buffer
* Returns: the number of bytes stored (excluding null)
* https://github.com/EZLippi/Tinyhttpd/blob/master/httpd.c
* */
/**********************************************************************/
int get_line(int socket, char *buffer, int size) {
int i = 0;
char c = '\0';
int n;
while ((i < size - 1) && (c != '\n')) {
/*
* 当没有数据时这里会阻塞
* */
n = recv(socket, &c, 1, 0);
/* DEBUG printf("%02X\n", c); */
if (n > 0) {
if (c == '\r') {
n = recv(socket, &c, 1, MSG_PEEK);
/* DEBUG printf("%02X\n", c); */
if ((n > 0) && (c == '\n'))
recv(socket, &c, 1, 0);
else
c = '\n';
}
buffer[i] = c;
i++;
} else
c = '\n';
}
buffer[i] = '\0';
return (i);
}
/**********************************************************************/
/*
* 创建socket连接并监听，使用ipv4协议
*
* 参数:
* port 端口号
* */
/**********************************************************************/
int create_listen(int port) {
int server_fd;
/*
* socket函数的方法签名
* int socket (int __family, int __type, int __protocol)
* __family 定义协议族
* __type 定义数据传输方式/套接字类型
* __protocol 定义传输协议
*
* 返回值是文件描述符
*
* */
server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (server_fd < 0) {
cout << "=> 连接失败" << endl;
}
/*
* 位于netinet/in.h
* 将套接字和IP、端口判断
*
* */
struct sockaddr_in server_addr{};
// 使用IPv4
server_addr.sin_family = AF_INET;
// 端口
server_addr.sin_port = htons(port);
// IP地址
server_addr.sin_addr.s_addr = htons(INADDR_ANY);
/*
* struct sockaddr* 位于socket.h
* bind()签名
* int bind (int, const struct sockaddr *__my_addr, socklen_t __addrlen);
* 第一个参数：socket文件描述符
* 第二个参数：struct sockaddr*
* 第三个参数：struct sockaddr* 长度
* */
int bind_error;
if ((bind_error = bind(server_fd, (struct sockaddr *) &server_addr, sizeof(server_addr))) < 0) {
cout << "=> 绑定socket异常:" << bind_error << endl;
close(server_fd);
exit(1);
}
// 设置监听
listen(server_fd, SOMAXCONN);
return server_fd;
}
void handler(int client, char* key, char *buffer) {
int len;
int content_length = -1;
char method[255];
char url[255];
/*
* i： 数组偏移量
* j： 行数偏移量
* */
size_t i, j;
i = 0;
/* 读取报文第一行 */
len = get_line(client, buffer, BUFFER_SIZE);
/*================== 解析请求方法 ==================*/
while (!isspace(buffer[i]) && i < sizeof(method) - 1) {
method[i] = buffer[i];
i++;
}
j = i;
method[i] = '\0';
cout << "请求方法:" << method << endl;
/*================== 解析请求方法 ==================*/
/*================== 解析url ==================*/
i = 0;
/* 跳过空格 */
while (isspace(buffer[j]) && (j < len))
j++;
while (!isspace(buffer[j]) && (i < sizeof(url) - 1) && (j < len)) {
url[i] = buffer[j];
i++;
j++;
}
url[i] = '\0';
cout << "URL：" << url << endl;
/*================== 解析url ==================*/
while ((len = get_line(client, buffer, BUFFER_SIZE))) {
if (buffer[0] != '\n') {
cout << buffer;
/* 设置Content-Length:的长度，截断数组取Content-Length的值 */
buffer[15] = '\0';
if (strcasecmp(buffer, "Content-Length:") == 0) {
char *stop;
content_length = strtol(&(buffer[16]), &stop, 10);
}
memset(buffer, 0, len);
} else {
break;
}
}
/*================== 解析请求数据 ==================*/
// 置零，下面读取请求数据
len = 0;
if (content_length > 0) {
do {
int tmp = recv(client, buffer, BUFFER_SIZE, 0);
len += tmp;
cout << buffer << endl;
memset(buffer, 0, tmp);
} while (len != content_length);
}
/*================== 解析请求数据 ==================*/
if (strcmp(key, url) == 0) {
system("git pull");
}
send(client, SEND_STR, sizeof(SEND_STR), 0);
close(client);
}
/**********************************************************************/
/*
* 功能：监听端口，接收http协议，当url与参数2匹配时执行git pull
*
* 注：写这个程序主要是为了学习socket和http协议，进而了解tomcat的io模型
*
* 参数1： 端口号
* 参数2： url地址
* */
/**********************************************************************/
int main(int argc, char **argv) {
int server_fd = create_listen(atoi(argv[1]));
int max_socket = server_fd;
struct sockaddr_in client_addr{};
struct timeval tv{};
socklen_t client_addr_len = sizeof(client_addr);
int client;
char buffer[BUFFER_SIZE];
int connect_amount = 0;
fd_set fd_read_set;
int fd_set[BACKLOG] = { 0 };
int ret;
int tmp;
while (true) {
cout << "i running" << endl;
FD_ZERO(&fd_read_set);
FD_SET(server_fd, &fd_read_set);
tv.tv_sec = 30;
tv.tv_usec = 0;
for (int i = 0; i < BACKLOG; ++i) {
if (fd_set[i] != 0) {
FD_SET(fd_set[i], &fd_read_set);
}
}
ret = select(max_socket + 1, &fd_read_set, NULL, NULL, &tv);
if (ret < 0) {
cout << "select" << endl;
break;
} else if (ret == 0) {
cout << "timeout" << endl;
continue;
}
tmp = 0;
for (int j = 0; j < connect_amount; ++j) {
if (FD_ISSET(fd_set[j], &fd_read_set)) {
handler(fd_set[j], argv[2], buffer);
FD_CLR(fd_set[j], &fd_read_set);
fd_set[j] = 0;
tmp++;
}
}
connect_amount -= tmp;
if (FD_ISSET(server_fd, &fd_read_set)) {
client = accept(server_fd, (struct sockaddr *) &client_addr, &client_addr_len);
if (client <= 0) {
cout << "=> accept 错误" << endl;
continue;
}
if (connect_amount < BACKLOG) {
fd_set[connect_amount++] = client;
if (client > max_socket) {
max_socket = client;
}
}
}
}
}
分析
有空再写