garrett_damore@tadpole.com wrote:

> > As noted above, we should set SR_INT_IE bit before calling hardclock()
> > if all interrupts were enabled (in status) and there is no other
> > pending interrupt (in ipending).
> >   
> 
> Hmm.... this sounds like maybe a port that isn't using the separate
> interrupts for soft interrupts?  Or am I misunderstanding something.
> 
> I guess I should take a good hard look at hardlock(9) implementation.

This is mentioned in the Design and Implementation of 4.4BSD.
Usually hardclock(9) schedules softclock() request, but
if there is no other interrupts to be handled, hardclock(9)
just lowers spl(9) to splsoftclock() and calls softclock() directly
to save overhead of an extra interrupt call for softintr.
(lines 881-904 in sys/kern/kern_clock)
---
Izumi Tsutsui