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
usage(char * name)12 void usage(char *name) {
13 printf ("Usage: %s cpunum\n", name);
14 }
15
main(int argc,char ** argv)16 int main(int argc, char **argv) {
17 unsigned 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 }
81