* Peter Zijlstra <[email protected]> wrote:
> On Fri, 2012-10-26 at 11:24 +0200, Ingo Molnar wrote:
>
> > So can we control this by restricting the users and avoiding
> > the overflow?
> >
> > A 2^64 result should be a *huge* amount of space already for
> > just about anything.
>
> I _think_ something like: dl_runtime * dl_deadline < U64_MAX,
> might do that. The question is, is this constraint usable?
> Simplified that boils down to about 4 seconds each, which
> sounds pretty much ok for most people -- but such statements
> usually come back to bite you (640kb anybody...).
We could constrain the precision, not the maximum value.
Having a 4 seconds hard limit is one thing, only having 10 nsecs
precision at 40 seconds is another.
Then the introduction of 128 bit math would be purely optional
and would address *that* limitation of precision, and only that
limitation. That way we could gladly skip 128 bit math.
Thanks,
Ingo
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