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To: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
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Cc: freebsd-questions@freebsd.org
Subject: Re: hyperthreading CPU and broken scheduling?
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Wojciech Puchar wrote:
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>>>
>> To enable hyperthreading, try setting the following in /etc/sysctl.conf:
>>
>> machdep.hyperthreading_allowed=1
>>
>> and reboot (or execute sysctl machdep.hyperthreading_allowed=1 by hand).
> did /etc/rc.d/sysctl start  and works.
>
> quite strange that FreeBSD disables hyperthreading at start.
>
>
IIRC there has been some discussion about possible vulnerabilities when 
hyperthreading is enabled. If you google around you will find it.