Linux Network programming-----> High Concurrency---> multi-process concurrent servers

It is necessary to write concurrent service-side programs while doing network service. The stability of the front-end client application is partly dependent on the client itself, and more depends on whether the server is fast enough and stable enough.

The common Linux concurrent Server model;

• • • Multi-Process Concurrent server

    • Multi-threaded Concurrent server

    • Select multi-channel I/O transfer server

    • Poll Multi-channel I/O forwarding server

    • Epool Multi-Channel I/O forwarding server.

This session mainly discusses the multi-threaded concurrent Server model:

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consider the following points when using multiple-process concurrent servers:

• • • Parent Process Maximum file description (the parent process needs close close Accpet The new file descriptor returned)

    • Number of processes created in the system (related to memory size)

    • Excessive process creation reduces overall service performance (process scheduling)

    .server code [pay special attention to function call return value in actual development]

#include  <stdio.h> #include  <stdlib.h> #include  <unistd.h> #include  <sys /types.h> #include  <sys/socket.h> #include  <arpa/inet.h> #include  <string.h># include <signal.h> #include  <sys/wait.h> #include  <ctype.h>/* * multi-process Concurrent server  *author: sea time 2016/06/18 */#define &NBSP;SERV_PORT&NBSP;9096//Server port number #define  serv_addr  "10.10.101.102"//server IP address void wait_process (int num) {//Reclaim sub-process while (0 <  Waitpid (0, null, wnohang)) {;}} Int main (int argc, char* argv[]) {pid_t pid;//creation process uses int lfd;//listener socket int cfd;/ /Client Socket struct sockaddr_in serv_addr;//server address family struct,  binding using struct sockaddr_in clie_addr;// The client address family structure, the receive connection uses the socklen_t clie_addr_len;//client address family size, the receive connection uses the charbuf[bufsiz];int n, i;//registration process to end the signal, Recycle end of subprocess signal (sigchld, wait_process);//Create Listener Socket//af_inet: Specify Ipv4//sock_stream: Specify tcp//0: The function will automatically specify the protocol Lfd = socket (AF_INET,&NBSP;SOCK_STREAM,&NBSP;0) According to the specified type, and/or all is initialized to 0bzero (&AMP;SERV_ADDR,  sizeof (SERV_ADDR));//Specify family: ipv4serv_addr.sin_family = af_inet;//Specify IP address and convert to network byte order Inet_pton (AF_INET ,  serv_addr, &serv_addr.sin_addr.s_addr);//Specify the port number and convert it to network byte order serv_addr.sin_port = htons ( Serv_port);//bind to the listener socket bind (lfd,  (struct sockaddr*) &serv_addr, sizeof (SERV_ADDR));// Specify a listening socket and set simultaneous connection upper limit//somaxconn:  system defaults to 128listen (lfd, somaxconn);//Loop Get connection while (1) {clie_addr_len =  sizeof (CLIE_ADDR);//Block Get Connection cfd = accept (lfd,  (struct sockaddr*) &clie_addr,  &clie_addr_len)///Play screen prompt to connect successfully printf ("%s:%d connected successfully!\n",  inet_ntop (Af_inet,  &clie_addr.sin_addr.s_addr, buf, sizeof (BUF)),  ntohs (Clie_addr.sin_port));//create Process PID  = fork ();//Sub-process if (0 == pid) {//child process close listener socket close (LFD); The parent process closes the connection socket close (CFD); Child processes communicate with client processes while (0&NBSP;==&NBSP;PID) {BzeRo (buf, sizeof (BUF));//Read messages sent by the client N = read (cfd, buf, sizeof (BUF));//Client off if (0  == n) {Close (CFD);p rintf ("%s:%d disconnect successfully!\n",  inet_ntop (AF_INET,  &clie_addr.sin_addr.s_addr, buf, sizeof (BUF)),  ntohs (Clie_addr.sin_port)); exit (1);} Convert to size for (i = 0; i < n; i++) {buf[i] = toupper (buf[i]);} Write back to the client (cfd, buf, n);} return 0;}

． Client

#include  <stdio.h> #include  <stdlib.h> #include  <arpa/inet.h> #include  < sys/types.h> #include  <sys/socket.h> #include  <string.h> #include  <unistd.h>/ * * socket Client Connection Server  */#define &NBSP;SERV_PORT&NBSP;9096//server port#define serv_addr  " 10.10.101.102 "//Server Ipint main (int argc, char* agrv[]) {int sfd;struct sockaddr_in  serv_addr;char buf[bufsiz];int n;//Create a network socket//af_inet: Specify Ipv4//sock_stream: Specify tcp// 0: The function will automatically specify the protocol Sfd = socket (AF_INET,&NBSP;SOCK_STREAM,&NBSP;0) According to the specified type;//Initialize Bzero (&serv_addr,  sizeof (SERV_ADDR));//Specify the family serv_addr.sin_family = af_inet;//specify the IP address and convert to network byte order Inet_pton (Af_inet, serv _ADDR,&NBSP;&AMP;SERV_ADDR.SIN_ADDR.S_ADDR);//Specify port and convert to network byte order serv_addr.sin_port = htons (SERV_PORT);// Connect to server Connect (sfd,  (struct sockaddr*) &serv_addr, sizeof (SERV_ADDR));//Read keyboard input while (Fgets (BUF,  sizeof (BUF),  stdin)  ! = null) {//write server send data write (Sfd, buf, strlen (BUF)); Bzero (Buf, sizeof (BUF));//read server send data n =  read (sfd, buf, sizeof (BUF));//server off if (0 == n) {close (SFD); break;} Output write (stdout_fileno, buf, n) to the screen, bzero (buf, sizeof (BUF));}}

This article is from the "Sea" blog, be sure to keep this source http://lisea.blog.51cto.com/5491873/1790697

Linux Network programming-----> High Concurrency---> multi-process concurrent servers