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 }
94