[Simh] SIMH-VMS on Linux (CentOS) Host running slow at times

[bsupnik at comcast.net]

The simulator nice's itself, and has done so for many, many years.  On both Windows and Unix, it runs at lower priority, to allow normal interactive jobs priority.

Pre-emption should not cause the simulator's clock to lose synchronization, unless the simulator is pre-empted for seconds or minutes at a time, or paused, or otherwise prevented from running on a regular basis.

Modern laptops that can dynamically vary their operating frequency can also screw up clock synchronization.

/Bob

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>    1. Re: SIMH-VMS on Linux (CentOS) Host running slow at times
>       (Kevin Handy)
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> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Mon, 09 Jul 2007 12:27:43 -0600
> From: Kevin Handy <kth at srv.net>
> Subject: Re: [Simh] SIMH-VMS on Linux (CentOS) Host running slow at
> 	times
> Cc: simh at trailing-edge.com
> Message-ID: <46927E1F.5000605 at srv.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> Michael Copini wrote:
> > In the past (two years ago) I was able to compile and run SIMH for vax
> > on a CentOS 4.5 system. In fact the system has run very nicely for the
> > last 18 month's in believe it or not a production environment in order
> > to extend the live of an inventory application that used to run on a
> > microvax 3100.
> >
> > Recently the VMS 7.3 on the SIMH 3.4 is running very slow. I have looked
> > at various things that might be the cause of this but can not find
> > anything. The only thing that I notice is that when the system is
> > reported as being slow, the system time is  of by sometimes several
> > hours. (Like yesterday the VMS time was 14:30 while the LINUX time was
> > 17:33. By shutting down the VMS and the SIMH and restarting it the
> > system get's it normal speed back.  But every so often in the last two
> > month's it is showing this slowness.
> >
> > Anybody with Idea's where to look for a solution. System has run  
> > unchanged for over a year without any problems.
> >   
> What else is running on that system? 'top' could be helpful here.
> 
> Could someone, wanting to use another application, be speeding up
> his run time by 'nice'ing the emulator? They'll never admit to it, but
> I've seen such in the past.
> 
> 
> 
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