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SubjectRe: [Patch 4/4] Tell GCC 4.1 to move unlikely() code to a separate section
In-Reply-To: <200602271639.34776.ak@suse.de>

On Mon, 27 Feb 2006 16:39:34, Andi Kleen wrote:
> On Monday 27 February 2006 16:31, Arjan van de Ven wrote:
> > This patch is more controversial I assume; it offers the option
> > to use the gcc 4.1 option to move unlikely() code to a separate section.
> > On the con side, this means that longer byte sequences are needed to jump
> > to this code, on the Pro side it means that the unlikely() code isn't sharing
> > icache cachelines and tlbs anymore.
>
> I don't think this will do anything because the default Makefile
> still has
>
> CFLAGS += -fno-reorder-blocks

This also won't work for functions that specify an explicit section name,
e.g. __sched, __kprobes etc. -- at least that's what the gcc 4.0.2 docs say.

--
Chuck
"Equations are the Devil's sentences." --Stephen Colbert

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