On 2018-03-07 10:47 AM, Christian König wrote: > Am 07.03.2018 um 09:42 schrieb Michel Dänzer: >> On 2018-03-06 07:23 PM, Christian König wrote: >> >>> E.g. the last time I tested it placing things into GTT still resulted >>> in quite a performance penalty for rendering. >> FWIW, I think the penalty is most likely IOMMU related. Last time I >> tested, I couldn't measure a big difference with IOMMU disabled. > > No, the penalty I'm talking about came from the ping/pong we did with > the scanout buffers. > > See when I tested this the DDX and Mesa where unmodified, so both still > assumed VRAM as placement for scanout BOs, but the kernel forced scanout > BOs into GTT for testing. > > So what happened was that on scanout we moved the VRAM BO to GTT and > after unpinning it on the first command submission which used the BO we > moved it back to VRAM again. In the meantime, I've had the same idea as Marek: Can't the kernel driver simply change the BO's preferred domain to GTT when scanning out from it? Then it won't move back to VRAM. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer
