SNA has matured a lot since its debut two years ago. With the forthcoming Intel 3.0 X.Org driver, this acceleration method is becoming the default over UXA. The OpenGL-based GLAMOR library just remains an experimental non-default option for the xf86-video-intel driver.
Our latest benchmarks have shown SNA continuing to work great and Chris Wilson's benchmarks of Cairo with SNA vs. UXA vs. GLAMOR show the same outcome.
Chris Wilson concluded on his blog, "The summary here is that Glamor offers a meagre improvement over UXA. However, both are still much slower on average than cairo-image, i.e. the performance attainable by using a single CPU core. It takes multiple threads inside the DDX to match the performance of cairo-image – this is due to the inherent inefficiencies of the current Render protocol. However, if we then utilize the render acceleration on the GPU (using SNA) we can indeed outperform cairo-image, on average about 2x faster and about 4x faster than UXA and Glamor. Thus SNA does deliver hardware acceleration that succeeds in offloading work onto the GPU (letting the CPU get on with other tasks) and performs faster than rendering everything with the CPU."