Re: [PATCH 0/4] new timeofday-based soft-timer subsystem

Nishanth Aravamudan
2005-06-15T15:02:10Z

On 15.06.2005 [08:30:20 +0200], Ulrich Windl wrote:
> On 14 Jun 2005 at 11:11, Nishanth Aravamudan wrote:
>
> [...]
> > Would it be beneficial to encapsulate the timer_list structure? That way
> > if the units change underneath and we eventually move to timer_fsecs
> > (for femtoseconds), we don't need to change all the callers of
> > set_timer_nsecs() again?
> [...]
>
> I don't think that we'll see a global clock with reliable femtosecond
> resolution (not to talk about accuracy) in the foreseeable computer
> generations. Even plain gigahertz RAM is quite some time away. So how
> would you distribute such high resolution time across CPUs? As long as
> a syscall takes significantly longer than 1ns, or has a jitter of more
> than 1ns, a higher resolution clock would be just a source of
> additional noise bits.

Thank you for your feedback, Ulrich. You are probably right that such a
hardware timesource probably is not going to be common any time soon. My
thoughts for encapsulation were just a possibility, and certainly not a
requirement for my patch.

I did not consider the problems of distributing that value, either. So,
I guess, I can leave encapsulation out of the current efforts :)

Thanks,
Nish