Subject: Re: [PATCH 2/2] powerpc: implement arch_scale_smt_power for Power7
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Joel Schopp <jschopp@austin.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>, Ingo Molnar <mingo@elte.hu>,
       ego@in.ibm.com, linuxppc-dev@lists.ozlabs.org,
       Peter Zijlstra <a.p.zijlstra@chello.nl>, linux-kernel@vger.kernel.org
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Date: Tue, 26 Jan 2010 15:23:56 +1100
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On Mon, 2010-01-25 at 11:50 -0600, Joel Schopp wrote:
> > Look at the cputhreads.h implementation ... Today we only support
> > power-of-two numbers of threads.
> >   
> I've run 3 threads using cpu hotplug to offline 1 of the 4.  It's 
> certainly a stupid idea, but there you go. 

Oh, you mean you need to use the actual online count ? In which case,
yes, you do indeed need to be a bit more careful... In this case though,
you're probably better off special casing "3" :-)

Cheers,
Ben.


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