error: work group size exceeds the maximum default — Win10 64bit about gpuowl HOT 5 CLOSED

If you want to run it on Intel HD GPU, it may be good to find a way to set group size above 256, in particular 512. I expect there is some way to do that, e.g. by setting some environment variable. This depends on the openCL driver (Intel), I don't know it.

But I really do need the 512 group size. I do not plan to reduce that, because it's important for fast running on AMD GPUs.

from gpuowl.

Right now gpuOwl requires WG 512; closing as there's nothing I think I can do here, except looking up documentation from Intel on how to enable that.

from gpuowl.

Sorry but I wasn't describing the issue clear enough:

It does work on my integrated Intel GPU but it does not work on my AMD Radeon HD 7850 Graphics Card. The error log is from the AMD card (as it also states in the first few lines of the log!)

from gpuowl.

Yes, sorry for my bad reading. IMO it's a driver issue. It does not accept, for some reason, a workgroup size of 512, which is needed by gpuOwl. I don't think there's much I can do to fix this in the program.

OTOH I bet I saw an environment variable that was lifting this restriction (256) on some AMD driver, but I can't seem to find it now by web search, which is annoying.

from gpuowl.

found it: GPU_MAX_WORKGROUP_SIZE
https://community.amd.com/thread/166244

So try running after an export like
export GPU_MAX_WORKGROUP_SIZE=512

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