20:19 <sarbes> Hi there. I was wondering if you could answer me some questions around afbc/pbo/texture streaming.

20:19 <sarbes> I'm in the process of modernizing Kodi's GUI engine. Currently, we do a lot of OpenGL 1.*/2.0-esque stuff, which I would like to replace with modern extensions.

20:20 <sarbes> One issue in particular is that Kodi drops frames on low power systems when loading new assets on runtime (posters/fanart and the like). I'm suspecting that this is due to the synchronous nature of "normal" texture uploads. I have a prototype which avoids stalling the render thread by copying the texture in a separate thread, using a pbo and glMapBuffer().

20:21 <sarbes> My questions would be:

20:21 <sarbes> 1) Does it make any sense to copy the texture this way, or is it not worth the hassle?

20:23 <sarbes> 2) Would it be preferable to stream such short lived textures via GL_PIXEL_UNPACK_BUFFER/GL_STREAM_DRAW, eating the higher BW cost by storing it linearly instead of risking a hiccup by tiling/compressing?

20:23 <sarbes> 3) Is it even possible to stream with mutable PBO's? https://gitlab.freedesktop.org/mesa/mesa/-/blob/main/src/mesa/main/bufferobj.c#L234 would suggest to me it is not.

20:24 <sarbes> 4) From my limited understanding, fencing could be an option to check if a texture is available to the GPU to avoid implicit synchronization. Is this an option for Mesa/Panfrost?

20:25 <sarbes> 5) (Bonus) Are immutable textures/buffers faster/better with Panfrost?

22:02 <robclark> not sure about panfrost, but freedreno will shadow (create a new copy) if you upload to busy textures, so it shouldn't really matter one way or another