perfstat_cpu interface

Selected fields from the perfstat_cpu_t structure include: Several other CPU-related metrics (such as number of forks, read, write, and execs) are also returned. For a complete list, see the perfstat_cpu_t section in the libperfstat.h header.

The following code shows an example of how the perfstat_cpu interface is used:

#include <stdio.h>
#include <stdlib.h>
#include <libperfstat.h>

int main(int argc, char *argv[]) {
   int i, retcode, cputotal;
   perfstat_id_t firstcpu;
   perfstat_cpu_t *statp;
   
   /* check how many perfstat_cpu_t structures are available */
   cputotal =  perfstat_cpu(NULL, NULL, sizeof(perfstat_cpu_t), 0);
   
      /* check for error */
   if (cputotal <= 0)
   {
        perror("perfstat_cpu");
        exit(-1); 
   }
  
   /* allocate enough memory for all the structures */
   statp = calloc(cputotal,sizeof(perfstat_cpu_t));
   if(statp==NULL){
	printf("No sufficient memory\n");
	exit(-1);
   }
   
   /* set name to first cpu */
   strcpy(firstcpu.name, FIRST_CPU);
   
   /* ask to get all the structures available in one call */
   retcode = perfstat_cpu(&firstcpu, statp, sizeof(perfstat_cpu_t), cputotal);
   
   /* check for error */
   if (retcode <= 0)
   {
        perror("perfstat_cpu");
        exit(-1); 
   }
   
   /* return code is number of structures returned */
   
   for (i = 0; i < retcode; i++) {
      printf("\nStatistics for CPU : %s\n", statp[i].name);
      printf("------------------\n");
      printf("CPU user time (raw ticks)  : %llu\n", statp[i].user);
      printf("CPU sys  time (raw ticks)  : %llu\n", statp[i].sys);
      printf("CPU idle time (raw ticks)  : %llu\n", statp[i].idle);
      printf("CPU wait time (raw ticks)  : %llu\n", statp[i].wait);
      printf("number of syscalls         : %llu\n", statp[i].syscall);
      printf("number of readings         : %llu\n", statp[i].sysread);
      printf("number of writings         : %llu\n", statp[i].syswrite);
      printf("number of forks            : %llu\n", statp[i].sysfork);
      printf("number of execs            : %llu\n", statp[i].sysexec);
      printf("number of char read        : %llu\n", statp[i].readch);
      printf("number of char written     : %llu\n", statp[i].writech);
      }
}

The program displays an output that is similar to the following example output:

Statistics for CPU : cpu0
------------------
CPU user time (raw ticks)  : 2585
CPU sys  time (raw ticks)  : 25994
CPU idle time (raw ticks)  : 7688458
CPU wait time (raw ticks)  : 3207
number of syscalls         : 6051122
number of readings         : 436595
number of writings         : 1284469
number of forks            : 4804
number of execs            : 5420
number of char read        : 1014077004
number of char written     : 56464273

Statistics for CPU : cpu1
------------------
CPU user time (raw ticks)  : 23
CPU sys  time (raw ticks)  : 794
CPU idle time (raw ticks)  : 7703901
CPU wait time (raw ticks)  : 42
number of syscalls         : 66064
number of readings         : 3432
number of writings         : 20620
number of forks            : 412
number of execs            : 51
number of char read        : 7068025
number of char written     : 217425

Statistics for CPU : cpu2
------------------
CPU user time (raw ticks)  : 0
CPU sys  time (raw ticks)  : 720
CPU idle time (raw ticks)  : 7704041
CPU wait time (raw ticks)  : 0
number of syscalls         : 0
number of readings         : 0
number of writings         : 0
number of forks            : 0
number of execs            : 0
number of char read        : 0
number of char written     : 0

Statistics for CPU : cpu3
------------------
CPU user time (raw ticks)  : 0
CPU sys  time (raw ticks)  : 810
CPU idle time (raw ticks)  : 7703950
CPU wait time (raw ticks)  : 0
number of syscalls         : 0
number of readings         : 0
number of writings         : 0
number of forks            : 0
number of execs            : 0
number of char read        : 0
number of char written     : 0

Statistics for CPU : cpu4
------------------
CPU user time (raw ticks)  : 243
CPU sys  time (raw ticks)  : 1799
CPU idle time (raw ticks)  : 7702802
CPU wait time (raw ticks)  : 62
number of syscalls         : 722482
number of readings         : 34416
number of writings         : 2994
number of forks            : 597
number of execs            : 453
number of char read        : 128511349
number of char written     : 2352602

Statistics for CPU : cpu5
------------------
CPU user time (raw ticks)  : 0
CPU sys  time (raw ticks)  : 209834
CPU idle time (raw ticks)  : 7676489
CPU wait time (raw ticks)  : 0
number of syscalls         : 729
number of readings         : 42
number of writings         : 0
number of forks            : 16
number of execs            : 1
number of char read        : 14607
number of char written     : 0

Statistics for CPU : cpu6
------------------
CPU user time (raw ticks)  : 0
CPU sys  time (raw ticks)  : 210391
CPU idle time (raw ticks)  : 7677505
CPU wait time (raw ticks)  : 0
number of syscalls         : 0
number of readings         : 0
number of writings         : 0
number of forks            : 0
number of execs            : 0
number of char read        : 0
number of char written     : 0

Statistics for CPU : cpu7
------------------
CPU user time (raw ticks)  : 0
CPU sys  time (raw ticks)  : 209884
CPU idle time (raw ticks)  : 7675736
CPU wait time (raw ticks)  : 0
number of syscalls         : 0
number of readings         : 0
number of writings         : 0
number of forks            : 0
number of execs            : 0
number of char read        : 0
number of char written     : 0