tools/testing/selftests/intel_pstate/aperf.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <math.h>
   3 #include <unistd.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <sys/types.h>
   7 #include <sys/stat.h>
   8 #include <fcntl.h>
   9 #include <sys/timeb.h>
  10 #include <sched.h>
  11 #include <errno.h>
  12
  13 void usage(char *name) {
  14         printf ("Usage: %s cpunum\n", name);
  15 }
  16
  17 int main(int argc, char **argv) {
  18         unsigned int i, cpu, fd;
  19         char msr_file_name[64];
  20         long long tsc, old_tsc, new_tsc;
  21         long long aperf, old_aperf, new_aperf;
  22         long long mperf, old_mperf, new_mperf;
  23         struct timeb before, after;
  24         long long int start, finish, total;
  25         cpu_set_t cpuset;
  26
  27         if (argc != 2) {
  28                 usage(argv[0]);
  29                 return 1;
  30         }
  31
  32         errno = 0;
  33         cpu = strtol(argv[1], (char **) NULL, 10);
  34
  35         if (errno) {
  36                 usage(argv[0]);
  37                 return 1;
  38         }
  39
  40         sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
  41         fd = open(msr_file_name, O_RDONLY);
  42
  43         if (fd == -1) {
  44                 perror("Failed to open");
  45                 return 1;
  46         }
  47
  48         CPU_ZERO(&cpuset);
  49         CPU_SET(cpu, &cpuset);
  50
  51         if (sched_setaffinity(0, sizeof(cpu_set_t), &cpuset)) {
  52                 perror("Failed to set cpu affinity");
  53                 return 1;
  54         }
  55
  56         ftime(&before);
  57         pread(fd, &old_tsc,  sizeof(old_tsc), 0x10);
  58         pread(fd, &old_aperf,  sizeof(old_mperf), 0xe7);
  59         pread(fd, &old_mperf,  sizeof(old_aperf), 0xe8);
  60
  61         for (i=0; i<0x8fffffff; i++) {
  62                 sqrt(i);
  63         }
  64
  65         ftime(&after);
  66         pread(fd, &new_tsc,  sizeof(new_tsc), 0x10);
  67         pread(fd, &new_aperf,  sizeof(new_mperf), 0xe7);
  68         pread(fd, &new_mperf,  sizeof(new_aperf), 0xe8);
  69
  70         tsc = new_tsc-old_tsc;
  71         aperf = new_aperf-old_aperf;
  72         mperf = new_mperf-old_mperf;
  73
  74         start = before.time*1000 + before.millitm;
  75         finish = after.time*1000 + after.millitm;
  76         total = finish - start;
  77
  78         printf("runTime: %4.2f\n", 1.0*total/1000);
  79         printf("freq: %7.0f\n", tsc / (1.0*aperf / (1.0 * mperf)) / total);
  80         return 0;
  81 }