Perry E. Metzger wrote:

>Frank Kardel <kardel@netbsd.org> writes:
>  
>
>>What would be gain if we would solve the frequency issue for TSC?
>>I think very little.
>>Why ?
>>Systems switching cpu frequency often are usually not interested in sub
>>microsecond time stamps.
>>    
>>
>
>That's not true. I really would like to be able to use cycle counters
>for time on my laptop for a number of reasons, including to be able to
>deal with multimedia applications better and better timestamps for
>profiling purposes.
>  
>
Yes I understand that motivation, but the system can only do a limited
number of gettimeofday() calls. Thus your effective resolution is limited.
Counters that run at a higher frequency than your highest call frequency
do not get  you much more benefit.

>  
>
>>Given the above limitations and effects a lower frequency counters like
>>the ACPI timer is just as good for those power saving environments.
>>    
>>
>
>How good is the ACPI timer?
>
>  
>
Runs at 3579545 Hz - counter ticks in ~279.4 ns

>Perry
>  
>
Frank