Subject: Re: separate statclock(9) with mips3 CP0 timer interrupt
To: None <>
From: Izumi Tsutsui <>
List: port-cobalt
Date: 04/22/2006 16:23:47
In article <> wrote:

> Out of curiosity, why not use CPU INT5 (CP0 clock interrupt) for
> hardclock? 

Not sure, but I guess:
- native OSes (Ultrix, WindowsNT etc.) don't use it
- MIPS1 CPUs don't have it (but have common external timers?)
- external timers could be more flexible then internal one
- no certain way to get precise CPU clock frequency on all models
  (but external timer clock is CPU indepenedent?)

> I never even knew there was support for a separate statistics clock.

It is mentioned in the D&I of 4.4BSD section 3.4,
but I don't know it's still useful for modern systems.
(the example in the book is hp300)
Izumi Tsutsui