On Tue, Jan 10, 2012 at 5:15 PM, Jose Fonseca <jfons...@vmware.com> wrote: > ----- Original Message ----- >> The flag is optional, it doesn't have to implemented by everybody. If >> we do the uploads in the state tracker, we will also do any required >> data transformation so that drivers don't have to do it at all. > > The same can be said for everything. > > I don't object adding yet another code path specific to a subset of hardware, > provided the benefits justify its existence. > > But honestly I'm not yet convinced of this, as there was no attempt to backup > with solid arguments why this matters. > > Furthermore this violates one of the principles gallium (and all 3D apis) > have of unmapping all resources when drawing.
If my idea violates one principle of all 3D APIs, this violates them all: http://www.opengl.org/registry/specs/AMD/pinned_memory.txt It allows reading user memory by hardware, and neither the driver nor the hardware is notified when the memory contents are changed by the user. BTW, I don't insist on this. I thought it would be a nice addition allowing user buffer uploads to be moved out of (especially radeon) drivers. If you really believe it's a bad optimization, feel free to revert. WIthout it, things wouldn't change for me at all... > >> > It looks to me that state trackers and/or drivers are not properly >> > using PIPE_USAGE_STREAM flag. As all cases where >> > PIPE_TRANSFER_MAP_PERMANENTLY would be used, the right way to do >> > it would be for the state tracker to set PIPE_USAGE_STREAM, the >> > pipe driver to recognize PIPE_USAGE_STREAM, and keep the mapping >> > permanently internally, making mapping/unmapping of such buffers >> > mere no-ops. >> >> We were doing that already and it wasn't good enough. Avoiding >> create+map+unmap+destroy *calls* have brought higher frame rates in >> apps with lots of draw operations. > > I understand the number map/unmap call is reduced. But how does this > interface change affect in any way the number of create/destroy calls? create = get_transfer destroy = transfer_destroy > > Also, please provide app name and performance figures w/ this change. OK. Torcs, the Forza track at the start. With u_upload_unmap before drawing: 21.4 - 22.1 fps Without u_upload_unmap: 22.7 - 23.1 fps The improvement is approximately 1.1 fps, which is probably too little for other people to care, but why throw it away? Marek _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
