Thanks for the reply. The delay of review will buy me some time to present
the aligned matrixf. It is true that these maths are not the largest
bottleneck even for our game, but they still are significant! especially
during heavy use of collision detection. I would like to know if Mathias
submission would be considered now as 99% of it is a c solution to reduce
the number of multiplies needed. It did bring the numbers down in our game
too. If so, I would like to write SSE forms of these new functions (e.g.
preMultTranslate) to the aligned matrixf and make them run even faster.
I would be interested in pursuing the traversal related methods, but I have
a feeling the solution would entail a design solution with C and not an SSE
one; However, if performance increase is not the top priority on anyone's
list I'd be willing to look into this and see if I can help.
James Killian
----- Original Message -----
From: Robert Osfield
To: "OpenSceneGraph Users" <osg-users@lists.openscenegraph.org>
Sent: Sunday, Aug 3, 2008 05:58 AM
Subject: Re: [osg-users] Using SSE within OSG
Hi Guys,
I've read through the correspondence on this issue, but won't dive in
with reviewing submissions on this topic till well after 2.6.0 is out
the door.
As a general note, there seems to be two related topics - data
alignment and then SSE instructions, they are of course related but
I'd suggest we tackle them separately.
As another general note, in my experience the most common bottleneck
of scene graph based applications is that of CPU memory bandwidth,
maths functions are much less of a bottleneck, and there cost in fact
largely hidden by the cost of waiting for the cache to be filled. The
performance profiles provided in this threaded suggest this as well -
with the traversal related methods being the biggest bottleneck. How
to address this bottleneck is a topic for another thread.
Robert.
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