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 #include <string.h>
  13 #include <time.h>
  14 #include "../kselftest.h"
  15
  16 #define MSEC_PER_SEC    1000L
  17 #define NSEC_PER_MSEC   1000000L
  18
  19 void usage(char *name) {
  20         printf ("Usage: %s cpunum\n", name);
  21 }
  22
  23 int main(int argc, char **argv) {
  24         unsigned int i, cpu, fd;
  25         char msr_file_name[64];
  26         long long tsc, old_tsc, new_tsc;
  27         long long aperf, old_aperf, new_aperf;
  28         long long mperf, old_mperf, new_mperf;
  29         struct timespec before, after;
  30         long long int start, finish, total;
  31         cpu_set_t cpuset;
  32
  33         if (argc != 2) {
  34                 usage(argv[0]);
  35                 return 1;
  36         }
  37
  38         errno = 0;
  39         cpu = strtol(argv[1], (char **) NULL, 10);
  40
  41         if (errno) {
  42                 usage(argv[0]);
  43                 return 1;
  44         }
  45
  46         sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
  47         fd = open(msr_file_name, O_RDONLY);
  48
  49         if (fd == -1) {
  50                 printf("/dev/cpu/%d/msr: %s\n", cpu, strerror(errno));
  51                 return KSFT_SKIP;
  52         }
  53
  54         CPU_ZERO(&cpuset);
  55         CPU_SET(cpu, &cpuset);
  56
  57         if (sched_setaffinity(0, sizeof(cpu_set_t), &cpuset)) {
  58                 perror("Failed to set cpu affinity");
  59                 return 1;
  60         }
  61
  62         if (clock_gettime(CLOCK_MONOTONIC, &before) < 0) {
  63                 perror("clock_gettime");
  64                 return 1;
  65         }
  66         pread(fd, &old_tsc,  sizeof(old_tsc), 0x10);
  67         pread(fd, &old_aperf,  sizeof(old_mperf), 0xe7);
  68         pread(fd, &old_mperf,  sizeof(old_aperf), 0xe8);
  69
  70         for (i=0; i<0x8fffffff; i++) {
  71                 sqrt(i);
  72         }
  73
  74         if (clock_gettime(CLOCK_MONOTONIC, &after) < 0) {
  75                 perror("clock_gettime");
  76                 return 1;
  77         }
  78         pread(fd, &new_tsc,  sizeof(new_tsc), 0x10);
  79         pread(fd, &new_aperf,  sizeof(new_mperf), 0xe7);
  80         pread(fd, &new_mperf,  sizeof(new_aperf), 0xe8);
  81
  82         tsc = new_tsc-old_tsc;
  83         aperf = new_aperf-old_aperf;
  84         mperf = new_mperf-old_mperf;
  85
  86         start = before.tv_sec*MSEC_PER_SEC + before.tv_nsec/NSEC_PER_MSEC;
  87         finish = after.tv_sec*MSEC_PER_SEC + after.tv_nsec/NSEC_PER_MSEC;
  88         total = finish - start;
  89
  90         printf("runTime: %4.2f\n", 1.0*total/MSEC_PER_SEC);
  91         printf("freq: %7.0f\n", tsc / (1.0*aperf / (1.0 * mperf)) / total);
  92         return 0;
  93 }