[coyotos-dev] coyotos.sleep, sleepTill, the epoch

[Valerio Bellizzomi]

On 12/02/2007, at 1.05, Sam Mason wrote:

>On Mon, Feb 12, 2007 at 12:15:46AM +0100, Valerio Bellizzomi wrote:
>> >> Something you definitely do NOT want is a 1ms granularity interrupt
to
>> >> maintain a tick counter. On current hardware this will account for a
>> >> measurable fraction of the machine.
>> >
>> >Yes, I was very surprised when Linux got this!
>> 
>> The hardware clock on a PC uses a low cost time base oscillator. It is
>> imprecise in any case.
>
>I think the main reason it was done under Linux was for scheduler
>improvements rather than increased timer/clock accuracy.
>
>> So why don't just grab the BIOS time-of-day when we need it?
>
>I think because you need to know the time surprisingly regularly, also
>as far as I can tell it will only give you the time to the nearest
>second anyway.  This is reasonable, but doesn't help the scheduler much.

The tick counter is also surprisingly prone to variations, this doesn't
help too.

val