I am working on improving 2D performances in KMS world and i am starting to think that we don't need the split btw read/write domain but only need one domain. My thinking is that there is no way for the kernel to properly synchronize data if memory read or write domain differ (for instance CPU read and GPU write) i think synchronizing btw CPU & GPU should be the matter of some other interface like the is_idle interface. So i want to change setdomain interface to only take 1 domain (doing same to all ioctl to request only 1 domain). So with this change if the userspace wants to access one buffer object to work on it, it should do the following :
setdomain(bo, CPU) wait_idle(bo) It would be up to the set domain to issue proper GPU flush if necessary, and wait idle should return only once flushing is done. Am i forgetting somethings about the motivations btw separate read/write domain ? Corollary the TTM priority stuff is i believe a wrong idea for radeon (could be usefull for others GPU but i don't have such feeling). So i would like to be able to disable it and move the knowledge in radeon kernel driver, here is my thinking on that : domain provided by userspace is a tip given to the kernel Then the kernel driver will be the one to choose where to put the buffer. For instance userspace can create an object in GTT space because this object will routinely accessed by the CPU, but at one point the GPU might need to write to it and most of the time we really want to put all buffer the GPU write to into VRAM. So kernel could move the object to VRAM for doing the rendering. Any thoughts on that ? I am working on patch to exercise this, i am especialy interested in performances improvement we can have in application which routinely call getimage for rendering, such as firefox. Cheers, Jerome ------------------------------------------------------------------------------ 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
