tools/testing/selftests/intel_pstate/aperf.c

   1 #include <math.h>
   2 #include <unistd.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <sys/types.h>
   6 #include <sys/stat.h>
   7 #include <fcntl.h>
   8 #include <sys/timeb.h>
   9 #include <sched.h>
  10 #include <errno.h>
  11
  12 void usage(char *name) {
  13         printf ("Usage: %s cpunum\n", name);
  14 }
  15
  16 int main(int argc, char **argv) {
  17         int i, cpu, fd;
  18         char msr_file_name[64];
  19         long long tsc, old_tsc, new_tsc;
  20         long long aperf, old_aperf, new_aperf;
  21         long long mperf, old_mperf, new_mperf;
  22         struct timeb before, after;
  23         long long int start, finish, total;
  24         cpu_set_t cpuset;
  25
  26         if (argc != 2) {
  27                 usage(argv[0]);
  28                 return 1;
  29         }
  30
  31         errno = 0;
  32         cpu = strtol(argv[1], (char **) NULL, 10);
  33
  34         if (errno) {
  35                 usage(argv[0]);
  36                 return 1;
  37         }
  38
  39         sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
  40         fd = open(msr_file_name, O_RDONLY);
  41
  42         if (fd == -1) {
  43                 perror("Failed to open");
  44                 return 1;
  45         }
  46
  47         CPU_ZERO(&cpuset);
  48         CPU_SET(cpu, &cpuset);
  49
  50         if (sched_setaffinity(0, sizeof(cpu_set_t), &cpuset)) {
  51                 perror("Failed to set cpu affinity");
  52                 return 1;
  53         }
  54
  55         ftime(&before);
  56         pread(fd, &old_tsc,  sizeof(old_tsc), 0x10);
  57         pread(fd, &old_aperf,  sizeof(old_mperf), 0xe7);
  58         pread(fd, &old_mperf,  sizeof(old_aperf), 0xe8);
  59
  60         for (i=0; i<0x8fffffff; i++) {
  61                 sqrt(i);
  62         }
  63
  64         ftime(&after);
  65         pread(fd, &new_tsc,  sizeof(new_tsc), 0x10);
  66         pread(fd, &new_aperf,  sizeof(new_mperf), 0xe7);
  67         pread(fd, &new_mperf,  sizeof(new_aperf), 0xe8);
  68
  69         tsc = new_tsc-old_tsc;
  70         aperf = new_aperf-old_aperf;
  71         mperf = new_mperf-old_mperf;
  72
  73         start = before.time*1000 + before.millitm;
  74         finish = after.time*1000 + after.millitm;
  75         total = finish - start;
  76
  77         printf("runTime: %4.2f\n", 1.0*total/1000);
  78         printf("freq: %7.0f\n", tsc / (1.0*aperf / (1.0 * mperf)) / total);
  79         return 0;
  80 }