test/select/speed.c

   1 /*
   2  * Test name: speed.c
   3  *
   4  * Objetive:  Test the time it takes for select to run.
   5  *
   6  * Description: This tests creates a number of udp connections and performs
   7  * a select call waiting on them for reading with timeout of 0.
   8  * This is done 10,000 thousands of times and then the average time it takes
   9  * is computed
  10  *
  11  * Jose M. Gomez
  12  */
  13
  14 #include <sys/types.h>
  15 #include <fcntl.h>
  16 #include <unistd.h>
  17 #include <sys/select.h>
  18 #include <sys/asynchio.h>
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <limits.h>
  22 #include <net/netlib.h>
  23 #include <time.h>
  24
  25 #define NUMBER 12
  26
  27 void main(void) {
  28         char *udp_device;
  29         int fd[NUMBER];
  30         fd_set fds_write;
  31         struct timeval timeout;
  32         time_t start_time, end_time;
  33         int i;
  34
  35         FD_ZERO(&fds_write);
  36         for (i = 0; i < NUMBER; i++) {
  37                 fd[i] = open("/dev/tty", O_RDWR);
  38                 if (fd[i] < 0) {
  39                         fprintf(stderr, "Error opening tty %d\n", i);
  40                         exit(-1);
  41                 }
  42                 FD_SET(fd[i], &fds_write);
  43         }
  44
  45         printf("Select will send 1 msg to terminal and %d to inet: \n", NUMBER);
  46         timeout.tv_sec = 0;
  47         timeout.tv_usec = 0;
  48         /* get initial time */
  49         start_time = time(NULL);
  50         for (i = 0; i < 32000; i++) {
  51                 select(NUMBER + 4, NULL, &fds_write, NULL, &timeout);
  52         }
  53         /* get final time */
  54         end_time = time(NULL);
  55         printf("The select call took on average: %f\n", (float)(end_time - start_time) /  32000.0);
  56         for (i = 0; i < NUMBER; i++) {
  57                 close(fd[i]);
  58         }
  59 }