common/writedata.c

///////////////////////////////////////////////////////////////////////////////
// Filename: writedata.c
///////////////////////////////////////////////////////////////////////////////
// Purpose: for performance measurements: write data read by 
//          readdata(). The time used to write all the data is displayed.
///////////////////////////////////////////////////////////////////////////////
// History:
// ========
//
// Date     Time     Name      Description   
// -------- -------- --------  ------------------------------------------------
// 96/02/27 18:57:56 muellerg: created
//
///////////////////////////////////////////////////////////////////////////////


// Feature test switches ///////////////////////////// Feature test switches //
    /* NONE */



// System headers /////////////////////////////////////////// System headers //

#include <stdlib.h>



// Local headers ///////////////////////////////////////////// Local headers //

#include "../common.h"
#include "readwritedata.h"


// Macros /////////////////////////////////////////////////////////// Macros //
    /* NONE */



// File scope objects /////////////////////////////////// File scope objects //
    /* NONE */



// External variables, functions, and classes ///////////// External objects //
    /* NONE */



// Signal catching functions ///////////////////// Signal catching functions //
    /* NONE */



// Structures, unions, and class definitions /////////////////// Definitions //
    /* NONE */



// Functions and class implementation /// Functions and class implementation //

/*
 * writedata(): write data which is read by readdata() and writes out how
 *              long it took to write all the data
 *              the function needs a file descriptor to read from, so it is
 *              only usable for IPC facilities which allow reading and writing 
 *              data to descriptors.
 *
 * in: name: base name for logfile(s)
 *      ext: extension (e.g. "read" or "write")
 *       fd: descriptor to write to
 *      pid: process to synchronize with (if 0, no synchronation is done,
 *           e.g. if processes run on different computers...)
 *           to use these facility the caller has to install a special
 *           signal handler with  synchronization_init();
 *
 *
 * return: true if everything is ok, else false
 *
 */

bool 
writedata(char *name, char *ext, int fd, pid_t pid)
{
    char *buffer=new char[size_max];
    if(!buffer) return false;
    
    int i, size;

    measurement mes(name, ext, measurement_max);

    for(size=1; size <= size_max; size*=2 )
    {
        if(pid)
        {
            // wait for start signal from other process
            synchronization_wait();

            // and acknowledge

            synchronization_signal_child(pid);
        }           


        // start timer

        mes.start(size, how_often);
        
        for(i=0; i < how_often; i++)
        {
            writen(fd, buffer, size);
        } 

        // store data about measurement

        mes.end();
    }

    mes.writeout_logfile();
    mes.writeout_plain_logfile();

    delete[] buffer;

    return true;    
}

// Main /////////////////////////////////////////////////////////////// Main //
    /* NONE */