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/*
* $Id: MHz.c,v 1.3 2003/06/09 22:02:36 davej Exp $
* This file is part of x86info.
* (C) 2001 Dave Jones.
*
* Licensed under the terms of the GNU GPL License version 2.
*
* Estimate CPU MHz routine by Andrea Arcangeli <andrea@suse.de>
* Small changes by David Sterba <sterd9am@ss1000.ms.mff.cuni.cz>
*
*/
#include <stdio.h>
#include <sys/time.h>
#include <string.h>
#include <unistd.h>
#ifdef __WIN32__
#include <windows.h>
__inline__ unsigned long timer_init();
#endif /* __WIN32__ */
#include "../x86info.h"
__inline__ unsigned long long int rdtsc()
{
unsigned long long int x;
__asm__ volatile (".byte 0x0f, 0x31" : "=A" (x));
return x;
}
void estimate_MHz(struct cpudata *cpu)
{
#ifndef __WIN32__
struct timezone tz;
struct timeval tvstart, tvstop;
#endif /* __WIN32__ */
unsigned long long int cycles[2]; /* gotta be 64 bit */
unsigned long microseconds; /* total time taken */
unsigned long eax, ebx, ecx, edx;
unsigned long freq = 1;
#ifdef __WIN32__
LARGE_INTEGER lfreq;
QueryPerformanceFrequency(&lfreq);
freq = lfreq.LowPart/1000000;
#endif /* __WIN32__ */
/* Make sure we have a TSC (and hence RDTSC) */
cpuid (cpu->number, 1, &eax, &ebx, &ecx, &edx);
if ((edx & (1<<4))==0) {
printf ("No TSC, MHz calculation cannot be performed.\n");
cpu->MHz = 0;
return;
}
#ifdef __WIN32__
timer_init();
cycles[0] = rdtsc();
microseconds = timer_init();
#else
memset(&tz, 0, sizeof(tz));
/* get this function in cached memory */
gettimeofday(&tvstart, &tz);
cycles[0] = rdtsc();
gettimeofday(&tvstart, &tz);
#endif /* __WIN32__ */
/* we don't trust that this is any specific length of time */
usleep(250000);
#ifdef __WIN32__
timer_init();
cycles[1] = rdtsc();
microseconds = timer_init() - microseconds;
#else
gettimeofday(&tvstop, &tz);
cycles[1] = rdtsc();
gettimeofday(&tvstop, &tz);
microseconds = ((tvstop.tv_sec-tvstart.tv_sec)*1000000) +
(tvstop.tv_usec-tvstart.tv_usec);
#endif /* __WIN32__ */
cpu->MHz = (int) (cycles[1]-cycles[0]) / (microseconds/freq);
if ((cpu->MHz % 50) > 15)
cpu->MHz = ((cpu->MHz / 50) * 50) + 50;
else
cpu->MHz = ((cpu->MHz / 50) * 50);
}
#ifdef __WIN32__
__inline__ unsigned long timer_init()
{
LARGE_INTEGER lcnt;
QueryPerformanceCounter(&lcnt);
return lcnt.LowPart;
}
#endif /* __WIN32__ */
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