[cairo] [PATCH] Altivec optimizations

Carl Worth cworth at cworth.org
Thu Mar 8 20:39:09 PST 2007

On Fri, 9 Mar 2007 03:39:23 +0000, Baz wrote:
> When I say nearly zero difference, I mean literally zero unless I perf
> -diff against several revisions ago (so that other things actually
> make a difference), just to proved to myself that perf-diff is still
> working. I've never seen it this consistent before, but there were
> some changes in 1.4. Am I right in thinking the image backend should
> be sufficient to demonstrate an effect of from your patch?

That would be a bug in perf-diff.

It examines the git has of the src/ directory to decide if anything
has changed, and if the hash is the same it decides there's no point
in checking, so you get exactly matching results.

This fails quite badly when you have a change that affects only

A cheesy workaround is to add a commit that adds whitespace to
src/cairo.h or something like that, and then compare the commit before
the altivec additions to the commit after the whitespace change.

And yes, it would be good to come up with a real fix for
cairo-perf-diff here.

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