On Thu, Apr 14, 2016 at 3:21 PM, Alex Deucher <[email protected]> wrote: > On Thu, Apr 14, 2016 at 3:29 AM, Michel Dänzer <[email protected]> wrote: >> On 14.04.2016 11:37, Michel Dänzer wrote: >>> On 12.04.2016 21:33, Marek =?UNKNOWN?B?T2zFocOhaw==?= wrote: >>>> >>>> URL: >>>> http://cgit.freedesktop.org/mesa/mesa/commit/?id=5a4b74d1ba2c156766a7a5dbfef099c7db5d6694 >>>> Author: Marek Olšák <[email protected]> >>>> Date: Mon Apr 11 19:56:07 2016 +0200 >>>> >>>> gallium/radeon: relax requirements on VRAM placements on APUs >>> >>> This change caused a bunch of ARB_shader_load_image_store piglit tests >>> to fail on my Kaveri, see some examples below. The incorrect values >>> seem consistent. >>> >>> I suppose some buffers end up in GTT instead of VRAM with this >>> change, but I'm not sure how that could cause problems. Any ideas? >> >> Also, with the code modified to use GTT only for everything but >> (potential) scanout buffers, the performance of Unigine Valley and the >> Unreal Engine 4 Elemental demo is reduced by about 30%. So the premise >> that GTT is about as fast as VRAM doesn't seem to hold true in practice >> (at least with Kaveri and presumably other (pre-)CIK APUs; maybe it's >> better with Carrizo and newer), which means that this change may cause >> performance of long-running processes to drop significantly over time. > > We need to make sure the buffers end up in WC GTT. The cache snoops > for coherent GTT reduce performance.
The numbers are with GTT WC. Marek _______________________________________________ mesa-dev mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/mesa-dev
