I get suspicious when anyone uses "real world benchmarks" and X in the same sentence because there is such a mix of drawing paths used in a running system today. My experience was that XAA ran benchmarks faster but the user experience was better with EXA (although that would obviously be biased by my own usage patterns).
One of the depressing things was that shadowfb still outperformed pretty much everything in a lot of scenarios, especially benchmarks, although it is obviously not a complete solution on its own. IIRC we've looked at accelerating just a couple of functions as you suggested (basically targetting fills, scrolls and blits) but that doesn't really work for discrete GPUs since the cost of moving between CPU and GPU domains is so much higher.
Some days I wish the trend towards drawing everything in OpenGL and ignoring X's drawing functions would move a little faster ;)
Sorry for hikacking this discussion ;)
Originally Posted by bridgman
For Java we have 3 backends supported on Linux.
- X11 (these days it basically falls back to XShmPutImage all the time)
Although I've written the XRender backend, I would clearly prefer to move to OpenGL directly.
However, beside being a lot slower than XRender for the typical small 2D primitives (text!!) the driver quality is a major issue.
Its broken with every other driver release, regardless of the manufacturer. Its something we can make available to early adaptors using a command-line switch, but certainly not enable it by default.
Things important for 2D simply don't get a lot attention.
All in all I really wish you the best for the Radeon driver. I am looking forward when those 2D performance issues will be a thing of the past and ... well ... I won't buy a new laptop for the next ~3 years ... I would be really happy if a Steamroller++ design would fit my needs ;)
This was the kind of hijack that makes it worth coming here, no worries.
One possible side effect of using glamor for X rendering is that the same kinds of issues which affect the Java OpenGL backend might be caught more quickly. Of course there are other possible side effects as well, including deciding that using glamor is too much of a pain ;)