source: trunk/minix/test/select/speed.c@ 11

/*
 * Test name: speed.c
 *
 * Objetive:  Test the time it takes for select to run. 
 * 
 * Description: This tests creates a number of udp connections and performs 
 * a select call waiting on them for reading with timeout of 0.
 * This is done 10,000 thousands of times and then the average time it takes
 * is computed
 *
 * Jose M. Gomez
 */

#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/select.h>
#include <sys/asynchio.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <net/netlib.h>
#include <time.h>

#define NUMBER 12

void main(void) {
        char *udp_device;
        int fd[NUMBER];
        fd_set fds_write;
        struct timeval timeout;
        time_t start_time, end_time;
        int i;

        FD_ZERO(&fds_write);
        for (i = 0; i < NUMBER; i++) {
                fd[i] = open("/dev/tty", O_RDWR);
                if (fd[i] < 0) {
                        fprintf(stderr, "Error opening tty %d\n", i); 
                        exit(-1);
                }
                FD_SET(fd[i], &fds_write);
        }       

        printf("Select will send 1 msg to terminal and %d to inet: \n", NUMBER);
        timeout.tv_sec = 0;
        timeout.tv_usec = 0;
        /* get initial time */
        start_time = time(NULL);
        for (i = 0; i < 32000; i++) {
                select(NUMBER + 4, NULL, &fds_write, NULL, &timeout); 
        }
        /* get final time */
        end_time = time(NULL);
        printf("The select call took on average: %f\n", (float)(end_time - start_time) /  32000.0);
        for (i = 0; i < NUMBER; i++) {
                close(fd[i]);
        }
}