Converting multiple CPU's to form single CPU's with double the GHz.

[infy101]

Hi All,

I'm fairly new to virtualisation and have a lot to learn still and one of the questions I have is if there is a way to 'combine' CPU's to get a higher GHz for a virtual machine? E.g. We have a 32 bit application running on a virtual machine which has 4 (lets say 2.5Ghz) CPU's (total of 10Ghz). The 32-bit application often runs at 100+ % on a RHEL virtual machine. Is it possible to somehow give the machine 2 x 5Ghz CPU's instead? This way the 32-bit app would run faster as it now has 5Ghz and not waiting for more cycles.

Regards,

Frank

[virtualg_uk]

Hi Frank,

When I look at virtual system I try to sometimes forget that they are virtual to aid with troubleshooting. This helps simplify the problem down.

In your scenario, no you cannot combine CPUs to get higher processor speeds. This is why cores exist. If you think of this as a physical system then you for sure cannot combing 2 CPUs together to get a higher clock speed.

What you can do is simply shutdown the VM and add more sockets/cores to your VM. This will allow for more simultaneous threads to be worked on, thus increasing performance but you will not be able to increase the clock speed of the CPUs.

I hope this helps.

[infy101]

Hi,

Thanks for the response!

The issue I have is that adding more cores will not help in this situation as the application in question only ever uses one of the CPU's - If I give it more it won't help. The idea is/was to give the application a more GHz so it maxes out at 5Ghz instead of 2.5. It's not able to use all cores.

Regards,

Frank