LuxMark v3.1: LuxRender propaganda with OpenCL

Discussions related to GPU Acceleration in LuxRender

Moderators: Dade, jromang, tomb, coordinators

Re: LuxMark v3.1: LuxRender propaganda with OpenCL

Postby pciccone » Thu Nov 26, 2015 11:32 am

Good catch. Yes, the .org version is much better
User avatar
pciccone
Developer
 
Posts: 1579
Joined: Wed Jan 13, 2010 11:02 am
Location: South Carolina

Re: LuxMark v3.1: LuxRender propaganda with OpenCL

Postby jeanphi » Thu Nov 26, 2015 4:25 pm

Hi,

I updated the header to point to the .org site.

Jeanphi
jeanphi
Developer
 
Posts: 7943
Joined: Mon Jan 14, 2008 7:21 am

Re: LuxMark v3.1: LuxRender propaganda with OpenCL

Postby acasta69 » Sun Dec 20, 2015 10:37 am

Hi,

I noticed something strange in the OpenCL mode for CPU only (Luxball scene): on one of my machines (Win 8.1 with AMD SDK), in spite of a decent score, the final image fails the check (more than 33% different pixels).
In C++ mode this does not happen: the image is validated.

I double checked on another machine (Win 7 with both Intel drivers and AMD SDK installed): it turns out that, depending on the choice of AMD or Intel CPU driver, the final image differs a lot, and fails the check when AMD is used.
In the attachments you can see what happens: there is a clear pattern in the out-of-focus part of the image when AMD is chosen.
Anyone ever noticed something similar? I've never seen something like that in real renders, I'm just curious about what could be going on, and if there can be some bug in AMD CPU drivers.

Thanks
Ale

OCL_Intel.jpg
Intel platform

OCL_AMD.jpg
AMD platform
Windows 10 64 bits, i7-4770 3.4 GHz, RAM 16 GB, GTX 970 4GB v382.05
acasta69
 
Posts: 299
Joined: Fri Dec 20, 2013 3:18 am

Re: LuxMark v3.1: LuxRender propaganda with OpenCL

Postby Dade » Sun Dec 20, 2015 2:28 pm

acasta69 wrote:In the attachments you can see what happens: there is a clear pattern in the out-of-focus part of the image when AMD is chosen.
Anyone ever noticed something similar? I've never seen something like that in real renders, I'm just curious about what could be going on, and if there can be some bug in AMD CPU drivers.


It looks like a bug in AMD CPU driver and the image validation process is supposed to exactly detect such a problem so I would say it is working as intended.

Aside from checking if you are using the latest AMD drivers, I would try also to disable all option under the "OpenCL Compiler Options" menu.
User avatar
Dade
Developer
 
Posts: 8404
Joined: Sat Apr 19, 2008 6:04 pm
Location: Italy

Re: LuxMark v3.1: LuxRender propaganda with OpenCL

Postby acasta69 » Sun Dec 20, 2015 4:37 pm

Thanks Dade,

it seems that it was triggered by the -cl-fast-relaxed-math flag.
I will also check what happens with more recent drivers: I have the AMD app sdk 2.9-1, but the 3.0 is available now...
Windows 10 64 bits, i7-4770 3.4 GHz, RAM 16 GB, GTX 970 4GB v382.05
acasta69
 
Posts: 299
Joined: Fri Dec 20, 2013 3:18 am

Re: LuxMark v3.1: LuxRender propaganda with OpenCL

Postby Dade » Mon Dec 21, 2015 2:58 am

acasta69 wrote:I will also check what happens with more recent drivers: I have the AMD app sdk 2.9-1, but the 3.0 is available now...


Now OpenCL drivers are part of standard AMD driver package: some year ago you had to install OpenCL SDK to have them but not anymore.
User avatar
Dade
Developer
 
Posts: 8404
Joined: Sat Apr 19, 2008 6:04 pm
Location: Italy

Re: LuxMark v3.1: LuxRender propaganda with OpenCL

Postby acasta69 » Mon Dec 21, 2015 3:17 am

Dade wrote:Now OpenCL drivers are part of standard AMD driver package: some year ago you had to install OpenCL SDK to have them but not anymore.

You mean the standard AMD Catalyst package?
Won't it conflict with nVidia drivers for the graphics card?
Windows 10 64 bits, i7-4770 3.4 GHz, RAM 16 GB, GTX 970 4GB v382.05
acasta69
 
Posts: 299
Joined: Fri Dec 20, 2013 3:18 am

Re: LuxMark v3.1: LuxRender propaganda with OpenCL

Postby Dade » Mon Dec 21, 2015 4:00 am

acasta69 wrote:
Dade wrote:Now OpenCL drivers are part of standard AMD driver package: some year ago you had to install OpenCL SDK to have them but not anymore.

You mean the standard AMD Catalyst package?
Won't it conflict with nVidia drivers for the graphics card?


Ah, ok, I was assuming had an AMD GPU.
User avatar
Dade
Developer
 
Posts: 8404
Joined: Sat Apr 19, 2008 6:04 pm
Location: Italy

Re: LuxMark v3.1: LuxRender propaganda with OpenCL

Postby acasta69 » Mon Dec 21, 2015 7:15 am

Dade wrote:Ah, ok, I was assuming had an AMD GPU.

Yes, I forgot to specify...
Actually I could use the Intel CPU drivers (and have also the integrated graphics card supported), but I use the SDK to build Lux locally.
By the way, I see that Intel also has an OpenCL SDK.
Since I would use it only to build Lux, do you think the Intel SDK is ok for that, or should I stick to the AMD (Windows 64 platform + Visual Studio 2013)?
Windows 10 64 bits, i7-4770 3.4 GHz, RAM 16 GB, GTX 970 4GB v382.05
acasta69
 
Posts: 299
Joined: Fri Dec 20, 2013 3:18 am

Re: LuxMark v3.1: LuxRender propaganda with OpenCL

Postby Dade » Mon Dec 21, 2015 8:02 am

acasta69 wrote:
Dade wrote:Ah, ok, I was assuming had an AMD GPU.

Yes, I forgot to specify...
Actually I could use the Intel CPU drivers (and have also the integrated graphics card supported), but I use the SDK to build Lux locally.
By the way, I see that Intel also has an OpenCL SDK.
Since I would use it only to build Lux, do you think the Intel SDK is ok for that, or should I stick to the AMD (Windows 64 platform + Visual Studio 2013)?


Any SDK should be fine. You have only to be careful with the version of the cl.hpp file included as it could be an old version and includes known bugs.
User avatar
Dade
Developer
 
Posts: 8404
Joined: Sat Apr 19, 2008 6:04 pm
Location: Italy

PreviousNext

Return to GPU Acceleration

Who is online

Users browsing this forum: No registered users and 4 guests