Hi! I wanted to get some comments about an idea to use dri2 that might improve some drawbacks on dri2 compared to dri1. What's motivating this is the following:
1) On some systems, X roundtrips are very costly. For example on via processors when running gears, X ends up at around 10% for just the reportdamage call of dri1. I see similar or worse results on vms, but since I'm not 100% sure how to interpret "top" in these cases those results might be insignificant. 2) Some dri clients, like XvMC, might not be interested in other information than whether the cliprects of the dri drawable have changed, and given the above, might not want to call the X server once per frame to get the dimensions, since that would double or triple the CPU-usage. 3) In some cases drawables might want to carry extra driver-dependent information. This could be shareable synchronization objects and offsets into kernel buffers used for sub-allocation. One way to fix this would be to have the X server set up a per-drawable sarea with the contents defined solely by the driver. That sarea could perhaps be a shmem object, or a (possibly sub-allocated) GEM/TTM bo. Protection of the sarea data could be handled by a per-sarea drm-like or futex-like lock. Like dri1, the dri2 client could then update the drawables or buffers only when needed, as indicated by a stamp in the sarea. This idea requires no extra dri2 or drm infrastructure, except perhaps for a way to arbitrate the per-sarea locks if a futex isn't used. (Some drm_lock.c code could be reused if needed). The existence and format of the per-drawable sareas would be up to the driver. In the case of the gallium state trackers it would be a matter of the dri- and xorg state tracker to agree upon existence and format of these sareas. Since it seems some people regard sareas as something very evil I'd like to get some feedback on this! It's only an idea at this stage. /Thomas ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
