root/tools/testing/selftests/intel_pstate/aperf.c

DEFINITIONS

1. usage
2. main

   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 #include <string.h>
  13 #include "../kselftest.h"
  14 
  15 void usage(char *name) {
  16         printf ("Usage: %s cpunum\n", name);
  17 }
  18 
  19 int main(int argc, char **argv) {
  20         unsigned int i, cpu, fd;
  21         char msr_file_name[64];
  22         long long tsc, old_tsc, new_tsc;
  23         long long aperf, old_aperf, new_aperf;
  24         long long mperf, old_mperf, new_mperf;
  25         struct timeb before, after;
  26         long long int start, finish, total;
  27         cpu_set_t cpuset;
  28 
  29         if (argc != 2) {
  30                 usage(argv[0]);
  31                 return 1;
  32         }
  33 
  34         errno = 0;
  35         cpu = strtol(argv[1], (char **) NULL, 10);
  36 
  37         if (errno) {
  38                 usage(argv[0]);
  39                 return 1;
  40         }
  41 
  42         sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
  43         fd = open(msr_file_name, O_RDONLY);
  44 
  45         if (fd == -1) {
  46                 printf("/dev/cpu/%d/msr: %s\n", cpu, strerror(errno));
  47                 return KSFT_SKIP;
  48         }
  49 
  50         CPU_ZERO(&cpuset);
  51         CPU_SET(cpu, &cpuset);
  52 
  53         if (sched_setaffinity(0, sizeof(cpu_set_t), &cpuset)) {
  54                 perror("Failed to set cpu affinity");
  55                 return 1;
  56         }
  57 
  58         ftime(&before);
  59         pread(fd, &old_tsc,  sizeof(old_tsc), 0x10);
  60         pread(fd, &old_aperf,  sizeof(old_mperf), 0xe7);
  61         pread(fd, &old_mperf,  sizeof(old_aperf), 0xe8);
  62 
  63         for (i=0; i<0x8fffffff; i++) {
  64                 sqrt(i);
  65         }
  66 
  67         ftime(&after);
  68         pread(fd, &new_tsc,  sizeof(new_tsc), 0x10);
  69         pread(fd, &new_aperf,  sizeof(new_mperf), 0xe7);
  70         pread(fd, &new_mperf,  sizeof(new_aperf), 0xe8);
  71 
  72         tsc = new_tsc-old_tsc;
  73         aperf = new_aperf-old_aperf;
  74         mperf = new_mperf-old_mperf;
  75 
  76         start = before.time*1000 + before.millitm;
  77         finish = after.time*1000 + after.millitm;
  78         total = finish - start;
  79 
  80         printf("runTime: %4.2f\n", 1.0*total/1000);
  81         printf("freq: %7.0f\n", tsc / (1.0*aperf / (1.0 * mperf)) / total);
  82         return 0;
  83 }