Multi-threaded usage in fastcgi

http://wdhdmx.iteye.com/blog/1477218

Official information: http://www.fastcgi.com/devkit/doc/overview.html

Http://www.fastcgi.com/devkit/doc/fastcgi-prog-guide/ap_guide.htm

Http://www.fastcgi.com/devkit/doc/fcgi-devel-kit.htm
0. Background

Content waiting to be communicated is added to the project, so the single request processing time has increased. Single-threaded processing of fcgi wastes CPU and user time, so multiple threads are required to process, reducing user queuing time.

Changing the part of the processing user request from a single thread to multi-threading requires a general understanding of whether the change will affect performance.

The

concludes that multithreading and threading are executed in almost the same way as a single thread, so multithreading does not pose an additional burden. 1. Single Thread processing steps 1.1 A simple single-threaded fcgi request C code   #include  <fcgi_stdio.h>      void  main (void)    {       int count = 0;       while (Fcgi_accept ()  >= 0)  {            printf ("content-type: text/html\r\n");            printf ("\ r \ n");           printf ("Hello  world!<br>\r\n ");           printf (" Request  number %d. ",  count++);       }       exit ( 0);  }   1.2 enters fcgi_accept.

Enter this fcgi_accept () method inside, in the file FCGI_STDIO.C. C code   int fcgi_accept (void)    {       //variable Indicates whether the request is received. Default is Fasle, do not receive requests        if (!acceptcalled)  {            //judge whether it is CGI, the variable is global static, next time will be used.            iscgi = fcgx_iscgi ();     The        //status changes to receive requests.            acceptCalled = TRUE;            //the end of the request, the value is emptied to assign the initial values.            atexit (&fcgi_finish);        } else if (iscgi)  {           // Not the first request, and it's a CGI program.            return (EOF);       }    &NBsp;   if (iscgi)  {           //cgi Initial assignment operation , do not care.            ...       } else  {           fcgx_stream *in, *out, * error;           //char**  string array.            FCGX_ParamArray envp;            //accept the request, this method is described below             int acceptresult = fcgx_accept (&AMP;IN,&NBSP;&AMP;OUT,&NBSP;&AMP;ERROR,&NBSP;&AMP;ENVP);            //receive failed, return <0, which is why the judgment on the loop is  while (fcgi_ Accept ()  >= 0)            if (acceptresult  < 0)  {               return acceptresult;           }           / /Assign the resulting data to the corresponding output, input, data.            FCGI_stdin->stdio_stream = NULL;            FCGI_stdin->fcgx_stream = in;            FCGI_stdout->stdio_stream = NULL;            FCGI_stdout->fcgx_stream = out;           FCGI_stderr->stdio_stream = NULL;           FCGI_stderr->fcgx_stream = error;           environ = envp;       }       //End        return 0;  }   1.3 fcgx_acceptWait for the method to receive the request, in FCGIAOO.C.

C code   static fcgx_request the_request;      int fcgx_accept (fcgx_stream &NBSP;**IN,FCGX_STREAM&NBSP;**OUT,FCGX_STREAM&NBSP;**ERR,FCGX_PARAMARRAY&NBSP;*ENVP)    {       int rc;//defines the variables that are returned.    whether     //has been initialized.        if  (! libinitialized)  {            rc = fcgx_init ();            if  (RC)  {                return rc;           }        }       //receive data, the following introduction        rc = fcgx_ Accept_r (&the_request);       //assigns a value to the corresponding stream and data.        *in = the_request.in;       *out = the_request.out;        *err = the_request.err;       *envp = the_request.envp;           return rc;  }   1.4 fcgx_accept_r ()

With the fcgiapp.c inside; C code  /*   *----------------------------------------------------------------------   *    * FCGX_Accept_r --   *   *       from http  server  receive a new request    * Results:   *       correct return of 0, Error return -1.   * Side effects:   *   *       The request is completed via fcgx_accept, the Input,output stream is created, and each is assigned to in   *      ,out, Err. Create parameter data is removed from Fcgx_getparam and given to ENVP.    *       do not save pointers and strings, they will be released in Fcgx_finish in the next request.    *----------------------------------------------------------------------   */   Int fcgx_accept_r (fcgx_request *reqdataptr)    {       if  (!libinitialized)  {           return -9998;       }          //The current reqdata to complete the request. Releases the content, initializes it.        fcgx_finish_r (reqdataptr);       //while        for  (;;)  {           //ipcFd  is the conduit of communication between the two sides, in the above Fcgx_finish_ R is assigned a value of-1.            if  (reqdataptr->ipcfd < 0)  {               int fail_on_ intr = reqdataptr->flags & fcgi_fail_accept_on_intr;                //receive a request, incoming socket, no request will wait here. That's the point, but I can't read it.                reqDataPtr->ipcFd  = os_accept (Reqdataptr->listen_sock, fail_on_intr, webserveraddresslist);               if   (reqdataptr->ipcfd < 0)  {                    return  (errno > 0)  ?  (0  - errno)  : -9999;                }           }            reqDataPtr->isBeginProcessed = FALSE;            reqdataptr->in = newreader (reqdataptr, 8192, 0);           fillbuffproc (reqdataptr->in);            if (!reqdataptr->isbeginprocessed)  {                goto tryagain;           }            {                //view the request type.                char *roleStr;                switch (ReqDataPtr->role)  {                    case FCGI_RESPONDER:                        roleStr =  "Fcgi_role=responder";                        break;   &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&Nbsp;       case fcgi_authorizer:                        rolestr =   "Fcgi_role=authorizer";                        break;                    case FCGI_FILTER:                         rolestr =  "Fcgi_role=filter";                        break;                    default:                        goto tryagain;               }                //creates a space for storing parameter querystring.                reqdataptr->paramsptr  = newparams (;  )              //the request type as a key-value join parameter.                putparam (reqDataPtr-> Paramsptr, stringcopy (ROLESTR));           }           //reads the input stream in a developed manner (where it stops, whether it needs to skip requests)             setreadertype (reqdataptr->in, fcgi_params);            //writes the parameter read to the Key=value.            if (Readparams (reqdataptr->paramsptr,  reqdataptr->in)  >= 0)  {                //jumps out of the loop, or waits for the next request.                break;            }               //releases these intermediate-generated things. Place IPCFD as -1.   tryagain:           fcgx_free ( reqdataptr, 1);          } /* for  (;;)  */       //assigns the remaining information to the value. Complete the start part of a request.        setreadertype (Reqdataptr->in, fcgi_stdin);        reqdataptr->out = newwriter (reqdataptr, 8192, fcgi_stdout);        reqdataptr->err = newwriter (Reqdataptr, 512, fcgi_stderr );       reqDataPtr->nWriters = 2;        reqDataPtr->envp = reqDataPtr->paramsPtr->vec;        return 0;  }   1.5 Fcgx_finish_r executed before closing the request

in the fcgiapp.c; C Code   VOID&NBSP;FCGX_FINISH_R (fcgx_request *reqdataptr)    {        int close;          if  (reqdataptr == null)  {           return;        }          close = !reqDataPtr->keepConnection;          if  (reqdataptr->in)  {            close |= fcgx_fclose (reqdataptr->err);            close |= fcgx_fclose (reqdataptr->out);        close |= fcgx_geterror (reqdataptr->in);       }           fcgx_free (reqdataptr, close);  }  

The basic end, can only understand the process. two multi-threaded requests 2.1 Multi-threaded Request Example

Official website multi-threading example, (HTTP://WWW.FASTCGI.COM/DEVKIT/EXAMPLES/THREADED.C)

Remove the excess output.

  C code   #define  THREAD_COUNT 20      Static int counts[thread_ count];      Static void *doit (void *a)    {        int rc;       FCGX_Request request;        fcgx_initrequest (&request, 0, 0);       for  (;;)        {           rc =  fcgx_accept_r (&request);              if   (rc < 0)                 break;           fcgx_fprintf (request.out,                "content-type: text/html\r\n"                "\ r \ n"                  "<title>FastCGI Hello! ");              sleep (2);            fcgx_finish_r (&request);       }        return NULL;  }      int main (void)    {        int i;       pthread_t id[THREAD_COUNT];           fcgx_init ();           for  (i = 1; i < thread_count; i++)             pthread_create (&id[i], NULL, doit,  (void*) i);           doit (0);       return 0;  }   2.2 Methods related to fcgi

In the Main method C code fcgx_init ();  Initilize the FCGX library. This was called by fcgx_accept () but must was called by the user when using Fcgx_accept_r ().

In multi-line thread: C code fcgx_request Request;