# hyperthreading



## Anonymous (Dec 14, 2008)

Hi!

I have a standalone computer with FreeBSD 7.0 and kernel is compiled with SMP option and hyperthreading is on by default (I tought that I need to put machdep.hyperthreading_allowed=1 in sysctl.conf).
And my question is: Do I need hyperthreading enabled on the standalone machine or performance would be better if I disable it?

Thanks in advance.


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## brd@ (Dec 14, 2008)

From the security side, you really only need to disable hyperthreading on a machine that multiple people will be using simultaneously, i.e. a shell server. 

Performance is a whole nother ball of worms. It will _probably_ be better with it enabled, but some apps can't really take advantage of it well. Threaded programming is hard, etc etc.


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## Anonymous (Dec 14, 2008)

brd@ said:
			
		

> From the security side, you really only need to disable hyperthreading on a machine that multiple people will be using simultaneously, i.e. a shell server.
> 
> Performance is a whole nother ball of worms. It will _probably_ be better with it enabled, but some apps can't really take advantage of it well. Threaded programming is hard, etc etc.



Thank you very much.


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