Computing cpu's clock in cycles per second

[Michael Miles]

JD wrote:
>
> On 09/27/2010 07:34 AM, Wade Hampton wrote:
>    
>> Did you look at using the RDTSC instruction to read the
>> cycle counter?
>>
>> http://en.wikipedia.org/wiki/Time_Stamp_Counter
>>
>> Sample this over an interval to get an estimate
>> of the clock frequency based on this counter.
>>
>> __inline__ unsigned long long int rdtsc()
>> {
>>     unsigned long long int x;
>>     __asm__ volatile (".byte 0x0f, 0x31" : "=A" (x));
>>     return(x);
>> }
>>
>> I use gettimeofday() calls to check the wall-clock time,
>> usleep(n) to sleep for a long time (second or more),
>> and rdtsc to compute the cycles....  Seems to work
>> well.
>>
>> Cheers,
>> --
>> Wade Hampton
>>      
> Thank you very much Wade.
> I confirm that using rdtsc, the delta in tsc values, divided by 60
> (using nanosleep)
> is  798283074.9833333333 ticks per second, which is almost iddentical
> to what is reported by cpuinfo:
> cpu MHz        : 798.244
>
> No matter what the load factor on the machine, even when the load
> reached 5 or  6,
> it is the same value.
> Well, that's what you get for buying a laptop from a crappy manufacturer
> that has put in it a fixed unprogrammable clock (oscillator), and put in a
> lame BIOS that provides no hooks for setting C2 C3 ...etc.
> I will certainly steer friends and family away from this manufacturer.
>
>
>    
I find the whole idea of a manufacturer purposely sabotaging a computer 
in this manner just disgraceful.

This one really takes the cake since "cool and quiet" and "powernow" was 
a big marketing scheme back then. You would think that the bios would at 
least have something to say about it

I wonder if the machine in question was on windows if the cool and quiet 
drivers would have something to enable/ disable them by software?
But then again if Bios does not support then that would be a no show too...



Very bad manufacturing screw up


Michael