Speed up System-Clock for Realtime-Simulation

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Speed up System-Clock for Realtime-Simulation

Postby aj22 » 15. Mar 2010, 13:21

Hi,

i'm developing a realtime-system (normally runnning on an embedded pc) and simulate it under windows using virtual box. I wonder if it is possible to manipulate the systemclock for the virtual machines (which are generated by software?) in order to speed up my real-time software (in detail all the sleeps and timeouts). Thanks for your help.

regards
aj
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Re: Speed up System-Clock for Realtime-Simulation

Postby seabhcan » 26. Jul 2010, 13:42

I'd be interested in doing this too, but for an XP box.

Any one know how to do it?
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Re: Speed up System-Clock for Realtime-Simulation

Postby gregdavisfromnj » 22. Mar 2011, 17:05

I think that is normally a physical function of a timer on a motherboard, which usually is supplied by a battery and an oscillator. So how to swap out the virtual oscillator with a different one? If your OS has a time service like NTP, or GA is installed and set to sync your guest and host clocks, this could be thwarted. Then again, if GA can manipulate the guest clock, why not modify the GA code to factor time in its updates?

I want to accomplish this, too, btw.

Maybe get really close to a black hole. Or is it really far?
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Re: Speed up System-Clock for Realtime-Simulation

Postby mpack » 22. Mar 2011, 17:49

You might find it useful to read section 9.11 of the user manual.
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Re: Speed up System-Clock for Realtime-Simulation

Postby gregdavisfromnj » 6. Apr 2011, 21:59

Yeah section 9.11 pretty much has the answer, complete with the warning that time warping increases the risk of nausea in guest OS.

Oh well, probably a bad idea, anyway. Any interaction with the outside world that is not also warped by the same factor will probably cause the problems alluded to. Like digital signatures with timestamps on-or-in network packets, or timeouts from regular speed systems appearing too slow to the hyper-drive VM.

thanks.
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