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