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

[Jonathan S. Shapiro]

On Mon, 2007-02-12 at 01:05 +0000, Sam Mason wrote:

> 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.

Wall clock time and scheduler time are completely unrelated. The
scheduler requires a precise interval timer. A surprising amount of
imprecision can be tolerated in a time of day clock.

In EROS, the time of day clock was maintained by the kernel. The current
time of day was periodically written to a page. In Coyotos we don't
currently plan to do this -- we plan instead to implement time of day in
an application.

The kernel still needs to maintain an accurate interval timer to support
the scheduler. It is likely that the kernel will capture ``current
interval time'' on every interrupt. This is the best that *any* kernel
can really do.
-- 
Jonathan S. Shapiro, Ph.D.
Managing Director
The EROS Group, LLC
+1 443 927 1719 x5100