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Re: NetBSD/vax vm for github testing



On 2025-01-11 16:24, Mouse wrote:
But it becomes a hard problem with simulations, since the code in RSX
is also assuming that all CPUs are executing all the time, and
simulation normally don't do that to the level required.  Bursty
behavior becomes a real problem in this context. On a single-cpu
machine, that is very much a non-problem.

I'd think a single-CPU machine would make it even more of a problem.
On a multiprocessor, the emulation can (whether explicitly or not) give
each emulated CPU its own real CPU, so the emulated cores _are_ all
executing at the same time.  But on a single-CPU machine, the closest
you're likely to get is for the emulation to alternate between cores.

You misunderstood. I meant a single-CPU emulated CPU. Not at all connected to how many CPUs the host system have. I agree with your thought that a multi-core host system have a better chance at making it work, but my experience have been that it's not even close to good enough for at least MP PDP-11 systems. It's just too unpredictable when the different emulated CPUs actually will be running.

  Johnny

--
Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email: bqt%softjar.se@localhost             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol



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