Messages in this thread | | | Date | Wed, 22 Mar 2006 07:30:06 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: [BUG] wrong bogomips values with kernel 2.6.16 |
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On Wed, 22 Mar 2006, Knut Petersen wrote: > > All Pentium M, Xeon up to model 2 and the P6 family increment with every > internal processor cycle.
Just to humor me. Try the bogomips loop in user space with something like the appended (make sure the frequency is fixed to the lowest frequency).
Linus --- #include <stdio.h> #include <sys/time.h>
#define read_tsc(r) asm volatile("rdtsc":"=A" (r))
int main(int argc, char **argv) { struct timeval a; unsigned long start, end; unsigned long mhz, low;
gettimeofday(&a, NULL); read_tsc(start); for (;;) { unsigned long usec; struct timeval b; gettimeofday(&b, NULL); usec = (b.tv_sec - a.tv_sec)*1000000; usec += b.tv_usec - a.tv_usec; if (usec >= 1000000) break; } read_tsc(end); end -= start; mhz = end / 1000000; low = end % 1000000; printf("TSC: %lu.%06lu MHz\n", mhz, low); return 0; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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