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
12void usage(char *name) {
13	printf ("Usage: %s cpunum\n", name);
14}
15
16int 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}