Re: Higher resolution timers

["Vesa Jääskeläinen" <chaac@nic.fi>]

Hi All,

Colin D Bennett wrote:
> To implement a nice GUI with some animations, it will be important to
> have a timer with a better resolution than 1/18 second (which appears
> to be the current GRUB timer resolution on the PC).
> 
> What would be the best way to do this? Possibilities that I am aware of
> are: 
>  * RDTSC instruction (must calibrate with RTC at startup?)
>  * HPET (complex to use?)
>  * RTC (can we set the timer interrupt rate to >18 Hz?)
> 
> Does anyone have any thoughts on these options?
> 
> I think that using the TSC (w/ RDTSC instruction) and calibrating it
> with a quick 2-3 RTC tick loop at startup might be the easiest option.

Perhaps non-x86 BIOS people could provide feedback how to get more 
detailed timer information on other platforms? So we could produce an 
API that would be portable.

At least RDTSC do not work on pre-pentium machines so at least some 
detection for this OP code would be required to determine best possible 
way to use timer service. I think we have cpuid module already, perhaps 
this could be used for that too...

Thanks,
Vesa Jääskeläinen