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Subject: Re: fsl booke MM vs. SMP questions
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Gabriel Paubert <paubert@iram.es>
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Date: Mon, 28 May 2007 20:28:19 +1000
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Cc: ppc-dev <linuxppc-dev@ozlabs.org>, Liu Dave-r63238 <DaveLiu@freescale.com>,
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On Mon, 2007-05-28 at 12:23 +0200, Gabriel Paubert wrote:
> On SMP with single die and integrated memory controllers (PASemi), 
> I'd bet that tlb invalidation broadcast is typically much cheaper 
> since no external signals are involved (from a hardware point of view
> it's not very different from a store to a shared cache line that has 
> to be invalidated in the cache of the other processors). 

Except that is often has strong locking requirements along with a race
or two to deal with when not having a HW reload on the TLB. So in the
case of Freescale BookE, it is really something that should be measured.

Ben.