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Re: Crash with OpenCL
Posted: Fri Feb 02, 2018 12:51 am
by david57
Ok, I reduced the max. path depth to 64 and worked fine with GPU and Path and Sobol sampler.
I got curious, set it to METROPOLIS sampler and worked fine with this settings:
Total Path Depth = 64
Diffused = 64
Glossy = 64
Specular = 64
Would be nice for max settings not able to go past 64 in those option boxes as you said.
Re: Crash with OpenCL
Posted: Sun Feb 17, 2019 11:23 am
by infinityeternity
I also have a problem with OpenCL rendering (viewport preview rendering). It freezes. I suppose this is due to CL_DEVICE_MAX_MEM_ALLOC_SIZE=536870912. But why is it only ~500 MB while my card has 2GB dedicated GPU memory?
Re: Crash with OpenCL
Posted: Sun Feb 17, 2019 11:27 am
by alpistinho
Re: Crash with OpenCL
Posted: Sun Feb 17, 2019 11:50 am
by infinityeternity
Is there a way to increase this value? It seems that CUDA is less limited in this sense.
Re: Crash with OpenCL
Posted: Sun Feb 17, 2019 11:50 am
by Dade
It was an hardware limit on some old AMD GPU too: the HD5870 wasn't able to allocate a single block of memory larger of 256MB even if it had 4GB of ram. It was happening because the memory access was handled like a texture map read (so there was limits like 16384x16384 max. texture map size).
Re: Crash with OpenCL
Posted: Sun Feb 17, 2019 11:56 am
by Dade
infinityeternity wrote: Sun Feb 17, 2019 11:50 am
Is there a way to increase this value? It seems that CUDA is less limited in this sense.
Yes, there is a LuxCore parameter to reduce the number of threads used (and so the amount of memory required for all GPUTask buffers). The name of the property is "opencl.task.count" and the value should be something like 65536. BlendLuxCore probably doesn't exposes the parameter so you should export the scene in text format, add the following line to .cfg file:
And than run the rendering with LuxCoreUI.
Re: Crash with OpenCL
Posted: Sun Feb 17, 2019 12:08 pm
by CodeHD
Dade wrote: Sun Feb 17, 2019 11:56 am
Yes, there is a LuxCore parameter to reduce the number of threads used (and so the amount of memory required for all GPUTask buffers).
Will that impact performance?
Re: Crash with OpenCL
Posted: Sun Feb 17, 2019 12:13 pm
by infinityeternity
Dade wrote: Sun Feb 17, 2019 11:56 am
... rendering with LuxCoreUI.
It would be nice to do this within Blender
Re: Crash with OpenCL
Posted: Sun Feb 17, 2019 12:24 pm
by Dade
CodeHD wrote: Sun Feb 17, 2019 12:08 pm
Dade wrote: Sun Feb 17, 2019 11:56 am
Yes, there is a LuxCore parameter to reduce the number of threads used (and so the amount of memory required for all GPUTask buffers).
Will that impact performance?
Yes, depend on the GPU but reducing the number of threads will slightly reduce the performance due to some additional CPU <=> GPU communication.