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Large buffers

Question asked by vanja_z on Jul 24, 2012
Latest reply on Jul 7, 2014 by jammyamerica

Question: Are there any plans to support large buffers (close to 100% of available memory) on AMD graphics cards? If not, why not?

 

This "feature" (as AMD likes to refer to common sense behaviour lacking in their products) is vital to many scientific computing applications including my area of interest, computational fluid dynamics (CFD). The "feature" is "available" on nVIDIA hardware (CUDA and OpenCL) and of course on CPUs and indeed on every other computational device I am aware of.

 

Currently OpenCL users are limited to 25% of device memory, the minimum required by the OpenCL specification.

http://www.khronos.org/registry/cl/sdk/1.1/docs/man/xhtml/clGetDeviceInfo.html

Although I believe CAL is not subject to this limit, it appears to be either becoming deprecated or simply broken:

http://devgurus.amd.com/thread/155198

http://devgurus.amd.com/thread/159311

It appears that there used to be an undocumented environmental variable GPU_MAX_ALLOC_SIZE that allowed users to increase this limit however it has disappeared as silently as it appeared.
http://devgurus.amd.com/thread/145052

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