[Intel-gfx] FireFox performance regressions XAA -> EXA -> UXA

[Alan W. Irwin]

On 2010-01-25 16:21-0500 Clemens Eisserer wrote:

> I did some comparisons using Carl's Firefox benchmark comparing
> Fedora-12 (updated) with Fedora-8 (updated) using official FireFox-3.6
> builds:
>
> Results are         XAA /      EXA /    UXA:
> GMail Inbox:     39ms / 100ms / 110ms
> tomsguide:        56ms / 158ms / 316ms
> Heise.de            12.6ms / 46ms / 53ms
> phoronix.com   13.4ms / 57ms / 100ms
>
> At least in this tests, XAA is at lot faster than both EXA/UXA. Keep
> in mind Fedora-8 still has an old pixman version, without all the SSE2
> optimizations added lately.

That's a pretty sobering comparison with XAA.  Factors of 3x to 7x
performance regressions are not good.

> Ok, XAA is not fair, its comparing apples with oranges.

I assume you are referring to the fact that the modern Intel stack has lots
of extra features.  However, the claim was made in the past that the modern
Intel stack should eventually be comparable in speed with XAA if you stuck
with real-world comparisons.

I hope Carl (who has been involved in optimization work for the Intel stack
before and made the real-world comparison point before) comments on these
results.  If he is unaware of anything special in these comparisons that
should favour XAA, and assuming he agrees with you that these are real-world
comparisons, then the next obvious question is whether that old claim about
eventual speed of the new intel stack was optimistic or not.  IOW, can we
ever expect to see speed improvements of 3x to 7x in the modern Intel stack
in order to become comparable to XAA speed again for comparisons like above?

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state implementation
for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
Linux Links project (loll.sf.net); and the Linux Brochure Project
(lbproject.sf.net).
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