On 24/05/17 08:27 PM, Christian König wrote: > Am 24.05.2017 um 13:03 schrieb Marek Olšák: >>> >> I think the final solution (done in fault_reserve_notify) should be: >> if (bo->num_cpu_page_faults++ > 20) >> bo->preferred_domain = GTT_WC; I agree something like that will probably be part of the solution, but I doubt it's quite that simple or that it's the only thing that can be improved. > I more or less agree on that, but setting preferred_domain permanently > to GTT_WC is what worries me a bit. > > E.g. imagine you alt+tab from a game to your browser and back and the > game runs way slower now because BOs are never moved back to VRAM. Right, permanently moving a BO to GTT might itself cause performance to drop down a cliff in some cases. It's possible that this is irrelevant compared to excessive buffer migration for CPU access though. > What we need is a global limit of number of bytes transfered per second > for swap operations or something like that. > > Or maybe a timeout which says when a BO was moved (either by swapping it > out or by a CPU page fault) only move it back after +n jiffies or > something like that. I also feel like something like this will be more useful than the number of CPU page faults per se. But I'm curious what Marek comes up with. :) -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer
