OS X and OpenCL
Da ich früher täglich mit 3D Programmen wie 3DS Max gearbeitet habe wollte ich natürlich wissen, weshalb meine NVIDIA Grafikkarte im cMP mit dem Luxrenderer bzw. LuxMark 3.1 unter OS X so schlechte OpenCL Werte und sogar massive Rendering-Fehler produziert.
Meine Anfrage an LuxMark wurde netterweise auch ziemlich schnell von David Bucciarelli, einem der Programmierer von LuxMark, beantwortet:
„Unfortunately, Apple uses very old and/or custom drivers for NVIDIA and AMD GPUs on MacOS. They often include bugs that have been already fixed on Windows/Linux.
There are a lot of people complaining about OpenCL status on MacOS: just type "apple opencl petition" on Google to have an idea of what people think about Apple OpenCL.
LuxMark most complex scene (and same time the medium version too) fails to render the right image because of the bugs. It is know problem (acknowledge even by Apple).
Cheers,
David“
An Open Letter to Tim Cook
(
http://www.blendernation.com/2015/05/04/an-open-letter-to-tim-cook/#prettyPhoto)
On the same day that
Jens Verwiebe decided to stop maintining the OS X binaries for Blender because of Apple's bad GPU support (don't worry, someone else has stepped in), the LuxRender team published an open letter to Apple CEO about the state of their support.
Paolo Ciccone writes:
We have found out that the OpenCL GPU drivers for OS X are broken and are unable to render but the simplest of scenes. With anything barely complex the driver simply crash. CPU rendering works fine.
This is not a problem of the GPU or even the software expertise of AMD or nVidia. It’s a mater of old drivers shipped with OS X. The same scenes with the same exact hardware render on Windows and even on Linux. Beautifully. This is because, on those other OSes, it’s possible to update the drivers independently. On OS X OpenCL is part of the OS and the drivers can only be updated by Apple. Apparently OpenCL is not at the same level of priority than providing new Emoji and so we are stuck with broken drivers.
We have tried to work with AMD (they are powerless in this) and even talked with some Apple engineers, but nothing happened.
So today I decided to email Tim Cook, the CEO of Apple, directly, because we can’t continue like this. Here is the text of my email:
Read the letter here.
More news from AMD: OpenCL support in OS X 'El Capitan’
(
http://www.blendernation.com/2015/07/16/more-news-from-amd-opencl-support-in-os-x-el-capitan/)
This is an amazing week - not only did AMD
help break up Cycles into smaller kernels, but now they've taken a big step towards proper support on OS X too!
Ton Roosendaal writes:
After having struggled with limited OpenCL support for years, the OS X driver team at AMD made a big step forward by supporting function calls in the OpenCL compiler now. This is in the Beta 3 release of El Capitan.
That means that Blender now can support the current Cycles render engine for Mac Pro (10.11) with similar GPU render quality as Cycles had for CUDA in the past years.
More info, and test download.
Note: the "split kernel" version of Cycles stays in development, this would be the preferred way to have Cycles work in the long term. That work isn't finished yet though. For as now, a "mega kernel" would (and is on OSX 10.11 now) outperforming the "split kernel" in both quality and speed.
Ich bin einfacher 2D/3D Grafiker und eben kein Techniker oder Programmierer - doch diese Artikel würden auch mir Laien die nachfolgenden LuxMark / OpenCL Ergebnisse etwas besser erklären:
