[Simh] newbie question about simh performance

[Johnny Billquist]

If I were to add my two cents, the problem is the large memory defined 
for the simh VAX system. I suspect this is larger than the working set 
in the host VMS system, meaning you will have lots of paging going on, 
which cause the whole thing to be I/O bound, even though the OP thinks 
it's a CPU bound problem.

Either reduce the memory of the simh VAX instance, or increase the 
working set of the host system, so that you don't page so much.

	Johnny

On 2016-08-17 21:49, khandy21yo wrote:
> I notice that you don't have a 'SET CPU IDLE=VMS' line.
>
> It really helps the host systems CPU usage.
>
> -------- Original message --------
> From: gérard Calliet <gerard.calliet at pia-sofer.fr>
> Date: 8/17/16 8:54 AM (GMT-07:00)
> To: simh at trailing-edge.com
> Subject: [Simh] newbie question about simh performance
>
> Hello,
>
> I use simh to emulate VMS software, just a compiler impossible to port
> out of VAX/VMS. The compiler uses a lot of CPU resource, and very few of
> the others resources, like IO.
>
> I see that my jobs consume, for example, 2mn of cpu, for 2 hours of
> elapsed time, which seems bizarre because there is not a lot of IO and
> the compile task is the only one on the emulated VAX.
>
> I run simh on itanium i4 OpenVMS, and I hoped I would have good
> performances on this fast computer.
> I see that the simh process running on OpenVMS itanium does a lot of
> (direct) IO.
>
> Perhaps I forgot some good parameters? My .ini is minimal :
>
> load -r ka655x.bin
> attach NVR ka655.nvr
> set cpu 512m
> set -L rq0 rauser=18000000
> attach rq0 datauser2.dsk
> set xq mac=08-00-2B-3C-96-78
> attach xq eth1
> b cpu
>
>
> Any help will be welcomed, advice, documentation...
>
> Thanks,
>
> Gérard Calliet
>
>
>
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-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol