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Date: Mon, 19 Nov 2007 08:19:11 -0500
From: Bill Moran <wmoran@potentialtech.com>
To: Dinesh Nair <dinesh@alphaque.com>
Message-Id: <20071119081911.5a147893.wmoran@potentialtech.com>
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References: <20071118111446.H4507@wojtek.tensor.gdynia.pl>
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	<20071119115723.0701c02a@prophet.alphaque.com>
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Cc: Manolis Kiagias <sonicy@otenet.gr>, freebsd-questions@freebsd.org,
	Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
Subject: Re: hyperthreading CPU and broken scheduling?
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In response to Dinesh Nair <dinesh@alphaque.com>:

> On Sun, 18 Nov 2007 12:29:32 +0200, Manolis Kiagias wrote:
> 
> > Wojciech Puchar wrote:
> > > i have machune with intel's CPU with hyperthreading.
> > >
> > > it is detected right, but only first thread is ever used.
> > >
> > > top shows at least 50% idle no matter what i run!
> > >
> > > what's wrong?
> > 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).
> 
> would an SMP kernel be required to properly use hyperthreading, or would
> just the above sysctl setting be enough ?

The SMP kernel is required as well.

-- 
Bill Moran
http://www.potentialtech.com