> On Dec 11, 2018, at 12:01 PM, Mark Pizzolato <[email protected]> wrote:
>
> ...
> Meanwhile, something else has changed relatively recently that doesn't
> seem to actually execute this code when the system starts. Specifically,
> I just observed:
> 1) Boot NetBSD 8.0
> 2) Boot took 100 seconds to get to a "login: " prompt.
> 3) I would normally expect that the system was pretty much idle at this
> point and the 100 seconds would have exceeded the 20 second calibration
> window the idle code needs to have elapsed before the system actually idles.
> 4) The system ran for another 80 seconds before idling actually kicked in.
>
> I have no idea what the system was doing during this 80 second period, but
> that is not how things worked when the code above was initially added to the
> NetBSD kernel.
>
> It is good that eventually the above code is engaged, so we don't really need
> to change anything else, but it would be interesting to understand what the
> system is actually doing...
>
> - Mark
I remember seeing unexpectedly long delays to idle in other simulators too.
PDP11 quite reliably kicks into idle quickly, but on a simulator I'm working on
(ELX8) which also has an explicit idle instruction it would take a minute or
so. The one difference I can think of is the clock period, 16 ms for PDP11
(given simulated line clock) but 10 ms on ELX8.
paul
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