From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?windows-1252?Q?Michel_D=E4nzer?= Subject: Re: [PATCH 0/5] radeon: Write-combined CPU mappings of BOs in GTT Date: Fri, 18 Jul 2014 12:07:56 +0900 Message-ID: <53C88F8C.40907@daenzer.net> References: <1405591275-14461-1-git-send-email-michel@daenzer.net> <53C7A0D0.6080202@vodafone.de> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <53C7A0D0.6080202@vodafone.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: mesa-dev-bounces@lists.freedesktop.org Sender: "mesa-dev" To: =?windows-1252?Q?Christian_K=F6nig?= Cc: mesa-dev@lists.freedesktop.org, dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org On 17.07.2014 19:09, Christian K=F6nig wrote: > Am 17.07.2014 12:01, schrieb Michel D=E4nzer: >> In order to try and improve X(Shm)PutImage performance with glamor, I >> implemented support for write-combined CPU mappings of BOs in GTT. >> >> This did provide a nice speedup, but to my surprise, using VRAM instead >> of write-combined GTT turned out to be even faster in general on my >> Kaveri machine, both for the internal GPU and for discrete GPUs. >> >> However, I've kept the changes from GTT to VRAM separated, in case this >> turns out to be a loss on other setups. >> >> Kernel patches: >> >> [PATCH 1/5] drm/radeon: Remove radeon_gart_restore() >> [PATCH 2/5] drm/radeon: Pass GART page flags to >> [PATCH 3/5] drm/radeon: Allow write-combined CPU mappings of BOs in >> [PATCH 4/5] drm/radeon: Use write-combined CPU mappings of rings and > = > Those four are Reviewed-by: Christian K=F6nig Thanks! >> [PATCH 5/5] drm/radeon: Use VRAM for indirect buffers on >=3D SI > = > I'm still not very keen with this change since I still don't understand > the reason why it's faster than with GTT. Definitely needs more testing > on a wider range of systems. Sure. If anyone wants to give this patch a spin and see if they can measure any performance difference, good or bad, that would be interesting. > Maybe limit it to APUs for now? But IIRC, CPU writes to VRAM vs. write-combined GTT are actually an even bigger win with dedicated GPUs than with the Kaveri built-in GPU on my system. I suspect it may depend on the bandwidth available for PCIe vs. system memory though. -- = Earthling Michel D=E4nzer | http://www.amd.com Libre software enthusiast | Mesa and X developer