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I know I can use VMWare or Hyper-V to run emulated versions of operating systems, and I have a fair amount of control over some of the hardware aspects.

What I would like to know is, how is it possible to have more control over the hardware emulation.

For example. I can adjust the amount of system ram using the above mentioned solutions, but how can I adjust for example the CPU. My dev machine is pretty powerful, more so than the servers my product is intended to run from in production, making it hard for me to diagnose potential performance issues during dev/test.

Having a way to create a virtual server that is not using all of the processing power of the host would be great.

Any ideas? Thanks for sharing

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up vote 4 down vote accepted

QEMU can support launching a VM with a specific processor (and architecture), I believe. Here's the documentation...

You could also look up quotas on processor use in the host machine (or on your application in the guest) to limit how much of the CPU can be taken up (or memory, etc.). Depends on the OS you're using, though, so you may have to google resource quote with the OS you're using it under.

None of this will be quite the same as purchasing a second hand or very cheap system for actual "live testing" on a resource limited system once you're at a stage to deploy, though, if you want to test something more real-world and verify that your tests under emulation are accurate. An old second hand PC of limited capability may even be had from an old school lab at your local school districts or a college or other facility...schools are notorious for having to run really old hardware and having to find ways to dispose of ancient systems legally since they usually have to be recycled in some way, not just tossed in a dump. For the price of a full featured virtualizer you can have an actual testbed :-)

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Great answer. I am sure some old desk top hardware at our company is due to expire sometime soon, rather than let it go to waste.... – JL. Feb 17 '10 at 22:05

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