Sure, I’ll look into running the benchmarks again. Iirc the patches had very little impact for my Intel systems. The tests I do is simply cairo-perf-trace (from http://cgit.freedesktop.org/cairo/) using the benchmarks in http://cgit.freedesktop.org/cairo-traces, with the cairo-xlib backend obviously.

Now that Grigori’s patches have been committed to upstream glamor, would you be able to refresh these benchmarks (I’m more interested in the effect on radeon, but any hardware works). Alternatively, if you could disclose/document your methodology I can try to recreate these benchmarks myself.

That should make for an interesting comparison on Baytrail…

To be more specific, on ARM hardware the EXA bookkeeping overhead (compared to having no EXA hooks installed by the DDX driver) costs roughly the same in terms of CPU usage as 1/3 of the whole work done by the cairo image backend. Which basically eliminates EXA as a viable option for even trying to implement any kind of 2D acceleration using it.

Well, the EXA layer is not much better. It also has a terrible CPU overhead.

Supporting new (and old) GPUs keeps me occupied for most of my time. SNA isn’t quite finished – optimisation is a never ending battle, but I have a few features planned to try and make DRI more efficient (to support pageflipping on a subset of connected monitors). The biggest crux I see at the moment is that Cairo does not meet the requirements of its users (i.e. there are gaps in our support of , SVG and PDF features) and that Render is inadequate for accelerating Cairo. In the post-X world, Cairo will need its own dispatch mechanism that would look very similar to a Render+. It’s too early to call where Cairo will end up – to go fast on a GPU, you have to design your entire interface around the limitations of the GPU – which is the opposite of Cairo’s hardware agnostic minimal interface. The tradeoff may simply be that Cairo remains best on the CPU with the “accelerated compositing” being done on the GPU. That still requires a lot of work in Mesa to make data transfer efficient, if we were to use Mesa for that task. Clear as mud!

Thanks in advance..

We look forward to your patches.