1
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
19void usage(char *name) {
20 printf ("Usage: %s cpunum\n", name);
21}
22
23int 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}
94
