[coyotos-dev] Input requested: interval timing

[Marcus Brinkmann]

At Fri, 14 Sep 2007 13:25:54 -0400,
"Jonathan S. Shapiro" <shap at eros-os.com> wrote:
> My intuition is that we should use the one-shot approach for now.
> Reactions?

As far as I heard, reprogramming the old PIC is not fast enough to
make one-shot timer programming feasible.  The APIC however is
designed for exactly that.  Microsoft published some documents on
this, eg:

http://www.microsoft.com/whdc/system/sysperf/apic.mspx
http://www.microsoft.com/whdc/system/sysperf/IO-APIC.mspx

And I believe the I/O APIC spec from Intel also goes into detail about
this aspect.

My suggestion is to use a one-shot approach in the internal kernel
API, and on systems that require it use a periodic timer to implement
that.  This seems more powerful than doing it the other way around.

Thanks,
Marcus