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#include <math.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/timeb.h>
#include <sched.h>
#include <errno.h>
void usage(char *name) {
printf ("Usage: %s cpunum\n", name);
}
int main(int argc, char **argv) {
int i, cpu, fd;
char msr_file_name[64];
long long tsc, old_tsc, new_tsc;
long long aperf, old_aperf, new_aperf;
long long mperf, old_mperf, new_mperf;
struct timeb before, after;
long long int start, finish, total;
cpu_set_t cpuset;
if (argc != 2) {
usage(argv[0]);
return 1;
}
errno = 0;
cpu = strtol(argv[1], (char **) NULL, 10);
if (errno) {
usage(argv[0]);
return 1;
}
sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
fd = open(msr_file_name, O_RDONLY);
if (fd == -1) {
perror("Failed to open");
return 1;
}
CPU_ZERO(&cpuset);
CPU_SET(cpu, &cpuset);
if (sched_setaffinity(0, sizeof(cpu_set_t), &cpuset)) {
perror("Failed to set cpu affinity");
return 1;
}
ftime(&before);
pread(fd, &old_tsc, sizeof(old_tsc), 0x10);
pread(fd, &old_aperf, sizeof(old_mperf), 0xe7);
pread(fd, &old_mperf, sizeof(old_aperf), 0xe8);
for (i=0; i<0x8fffffff; i++) {
sqrt(i);
}
ftime(&after);
pread(fd, &new_tsc, sizeof(new_tsc), 0x10);
pread(fd, &new_aperf, sizeof(new_mperf), 0xe7);
pread(fd, &new_mperf, sizeof(new_aperf), 0xe8);
tsc = new_tsc-old_tsc;
aperf = new_aperf-old_aperf;
mperf = new_mperf-old_mperf;
start = before.time*1000 + before.millitm;
finish = after.time*1000 + after.millitm;
total = finish - start;
printf("runTime: %4.2f\n", 1.0*total/1000);
printf("freq: %7.0f\n", tsc / (1.0*aperf / (1.0 * mperf)) / total);
return 0;
}
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