Going forward, remember Chris W's comment that (paraphrasing a bit) Glamor is a good fit for big-ass GPU hardware (eg SI). Also note that some people are looking at initial patches for Glamor vs years of work on other architectures and extrapolating that "it's gonna be that way forever".
Last edited by bridgman; 07-30-2012 at 01:58 PM.
I count two wins for glamor and the rest are losses (vs Radeon EXA).
I'm aware, and you should be too, but yet you said above "I guess I don't understand the pushback".Also note that some people are looking at initial patches for Glamor vs years of work on other architectures and extrapolating that "it's gonna be that way forever".
It's entirely because of that. Users live in the now, saying that "in the future it will be bliss" is just talk, the "results now" show that glamor is worse in performance, and that it tears.
Option "RenderAccel" has some performance issues.
But it's not just performance. Reliability is also important. Do you remember a recent fallout of bugs in hardware accelerated RENDER implementations, which was just triggered by upgrading to recent cairo-1.12? Do you know that many linux distros are still patching cairo to disable the use of server side hardware accelerated gradients because the gradients are screwed up in the drivers even now? Software rendering is not totally bug free, but it is doing a lot better on the reliability front.
EXA does not even provide the infrastructure to accelerate gradients or trapezoids at the moment. They weren't used much previously because very few drivers (if any) implemented acceleration for them; hence they weren't tested much outside of sw rendering. Software rendering works because it's the reference implementation; that's how the features like gradients were added in the first place. Glamor has the infrastructure to support gradients and trapezoids already which is another reason it is attractive.
OK, in any case it's nice to have multiple alternatives. So you are of course free to try your luck with Glamor. With only one important condition: we need much better tools for automated correctness validation of RENDER implementations. Otherwise it is a real recipe for disasterGlamor has the infrastructure to support gradients and trapezoids already which is another reason it is attractive.