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c#aleagpu

Alea GPU Memory Allocation Limit

I am using Alea GPU with a GTX-1081ti, which has 11GB of global memory.

When I use the Alea Gpu.Default.Allocate method to allocate memory on the GPU, when I get up near 3+ GB I get an "out of memory" error.

My code is:

private static int Length = 2147000000;
...
var gpu = Gpu.Default;    
gpu.Allocate<int>(Length);

This should allocate about 8GB of GPU RAM, but it gives a CUDA out of memory exception. I've tried lower Length values, and based on the report from Task Manager the GPU Dedicated Memory only goes up to around 3 GB before it gets the error.

However, when I do the same with raw CUDA code (outside of Alea), my limit is a bit over 80% of 11 GB, or almost 9 GB (since W10 limits the allocation).

Does anyone know why I'm getting an "out of memory" error at only 3 GB?

Thanks.

Solution

  • (Putting into an answer since it seems to have solved your issue)

    It sounds like you may be compiling in 32 bit mode. Make sure you are are using a 64-bit OS and compiling in 64-bit mode. You wouldn't be the first to accidentally compile in 32-bit mode :)