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SubjectRe: [PATCH 11/11] ARM: Get rid of .LCcralign local label usage in alignment_trap macro
On Mon, Jul 30, 2012 at 03:15:44PM +0100, Russell King - ARM Linux wrote:
> On Mon, Jul 30, 2012 at 04:58:20AM -0700, Anton Vorontsov wrote:
> > This makes the code more izolated.
> >
> > The downside of this is that we now have an additional branch and the
> > code itself is 8 bytes longer. But on the bright side, this new layout
> > can be more cache friendly since cr_alignment address might be already
> > in the cache line (not that I measured anything, it's just fun to think
> > about it).
>
> The caches are harvard, so mixing data and code together does not increase
> performance. Having data which is used by the same code in the same cache
> line results in better performance.
>
> The additional branch will also cause a pipeline stall on older CPUs.
>
> So no, I don't see any way that this is a performance improvement. Please
> leave this as is.

Sure, will drop it.

Thanks!

--
Anton Vorontsov
Email: cbouatmailru@gmail.com


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