Hidden ATI Feature For Textured XRendering

Earlier this week we published benchmarks of the XRender extension using NVIDIA's latest beta Linux driver, which had a substantial performance boost thanks to Render improvements with this latest driver. One of the questions that have since come up is how ATI/AMD's binary Linux driver compares when using this X extension. Well, right now, it lags behind NVIDIA, but a Phoronix Forums member has discovered a hidden ATI Linux option that should yield XRender performance gains.

This option, which hasn't been formally introduced by AMD, is TexturedXrender. This forum member, ejs1920, had also mentioned the Textured2D option; however, we know that has been in the fglrx driver for the past few months. There was a similar situation to this back in the days of fglrx 8.25.18 with not only the Dynamic Display Management Options being a hidden feature, but so was TexturedVideo. These features were not officially introduced then as they were still being finalized, which we imagine is a similar situation right now for TexturedXrender.

On the Phoronix Forums, ejs1920 had reported an 80% performance boost when using the x11perf benchmark during the aa10text test, which measures glyph compositing performance. In our testing thus far when enabling TexturedXrender, the only render_bench test where we found a large difference was with Xrender doing non-scaled over blends.

Aside from that render_bench test, we found no other performance gains thus far, but have only begun exploring this TexturedXrender option. If you are interested in trying out TexturedXrender, add Option "TexturedXrender" "true" to the device section of your xorg.conf. We don't believe that this option will be formally introduced in the ATI Linux Catalyst driver for a few more months.