The following procedure compiles running in the VC60, Console mode. You can try it, it is very accurate.
#include
#include
Float measure_clock_speed ();
Int main (void)
{
Printf ("THE CPU IS Running In% F MHz", Measure_Clock_Speed ());
GetChar ();
Return 1;
}
Float measure_clock_speed ()
// -------------------------------------
{
Unsigned long Ticks;
Unsigned long cycles;
Unsigned long stamp0,
Stamp1;
Unsigned long freq = 0;
Unsigned long freq2 = 0;
Unsigned long freq3 = 0;
Unsigned long Total;
Unsigned long Tries = 0;
Large_integer t0, t1;
Large_integer count_freq;
if (! queryperformancefrequency (& count_freq))
{
Return 0.0F;
}
Unsigned long priority_class = getpriorityclass (getcurrentprocess ());
Long thread_priority = GetthreadPriority (getCurrentThread ());
SetPriorityClass (GetCurrentProcess (), realtime_priority_class;
SetthreadPriority (getCurrentThread (), thread_priority_time_critical;
DO
{
Tries ;
FREQ3 = FREQ2;
FREQ2 = FREQ;
QueryperFormanceCounter (& T0);
T1.LOWPART = T0.LOWPART;
T1.highpart = t0.highpart;
While (unsigned long) T1.LOWPART - (unsigned long) T0.LowPart <50)
{
QueryperFormanceCounter (& T1);
}
_asm
{
RDTSC
Mov Stamp0, EAX
}
T0.LowPart = T1.LowPart; // Reset Initial
T0.Highpart = T1.Highpart; // Time
While (unsigned long) t1.lowpart- (unsigned long) T0.LowPart <1000)
{
QueryperFormanceCounter (& T1);
}
_asm
{
RDTSC
Mov Stamp1, EAX
}
Cycles = stamp1 - stamp0;
Ticks = (unsigned long) t1.lowpart - (unsigned long) t0.lowpart;
Ticks = Ticks * 100000;
Ticks = ticks / (count_freq.lowpart / 10); if (ticks% count_freq.lowpart> count_freq.lowpart / 2)
{
Ticks ; // Round Up if Necessary
}
FREQ = cycles / ticks; // cycles / us = MHz
IF (Cycles% Ticks> Ticks / 2)
{
Freq ; // Round Up if Necessary
}
Total = (FREQ FREQ2 FREQ3);
WHILE ((Tries <3) || (Tries <20) && ((ABS (3 * Freq-Total)> 3)
||
(ABS (3 * Freq2-Total)> 3) || (ABS (3 * Freq3-Total)> 3)))))
IF (Total / 3! = (Total 1) / 3)
{
Total ; // Round Up if Necessary
}
// restore the thread priority
SetPriorityClass (), priority_class;
SetthreadPriority (GetCurrentThread (), Thread_Priority;
Return float / 3.0f;
}
