Newbie - Trying to use CUDA.NET

Accelerated Computing CUDA CUDA Programming and Performance
1

Hi!

I have just started using cuda for a project at work.

We have a .net application where we would like to use cuda to do some image analysis using cuda.net.

Though I have a hard time getting it to work.

By some reason I can’t initialize cuda in my constructor of my class. Get Error invalid context if I try to do like that.

Do I have to make new cuda object for every frame?

Then if I make a new cuda object for every frame I get a memory leak and after ~10-20 frames cuda crashes due to out of memory. Do I have to something more than just cuda.Free()?

I can see that it releases all the memory for the array, it is something else that eats mem.

If i check how much memory I have right after “new CUDA.CUDA(0, true)” and then after i release the memory in the device for the array its the same. But then at the next frame it has less memory after “new CUDA.CUDA(0, true)” and so on until it crashes. What am I doing wrong?

My thought was to have it something like this:

using GASS.CUDA;

using GASS.CUDA.Types;

using System.IO;

namespace Imaging

{

	public class CudaClass

	{

		private GASS.CUDA.CUDA cuda;

		private CUfunction threshold;

		public CudaClass()

		{

			InitializeCuda();

		}

		public void dispose()

		{

			if (this.cuda != null) {

				this.cuda.Dispose();

				this.cuda = null;

			}

		}

		private void InitializeCuda()

		{

			Init and select 1st device.			

			cuda = new GASS.CUDA.CUDA(0, true);

			// load module

			cuda.LoadModule(Path.Combine(Environment.CurrentDirectory, "test_kernel.cubin"));

			threshold = cuda.GetModuleFunction("threshold");

		}

		public void DoCudaStuff(float[] source, int frameWidth , int frameHeight )

		{			

			int frameSize = frameWidth * frameHeight;

			// do some CUDA stuff

			try

			{

				// Init and select 1st device.

				//CUDA.CUDA cuda = new CUDA.CUDA(0, true);

				// load module

				//CUmodule module = cuda.LoadModule(Path.Combine(Environment.CurrentDirectory, "test_kernel.cubin"));

				//CUfunction threshold = cuda.GetModuleFunction(module, "threshold");

				

				// copy host memory to device

				CUdeviceptr deviceInData = cuda.CopyHostToDevice<float>(source);

				int block_size_x = 496;

				int block_size_y = 476;

				int n_blocks_x = frameWidth / block_size_x + (frameSize % block_size_x == 0 ? 0 : 1);

				int n_blocks_y = frameHeight / block_size_y + (frameSize % block_size_y == 0 ? 0 : 1);

				// setup execution parameters

				cuda.SetFunctionBlockShape(threshold, n_blocks_x, n_blocks_y, 1);

				cuda.SetParameter(threshold, 0, (uint)deviceInData.Pointer);

				cuda.SetParameter(threshold, IntPtr.Size, (uint)frameWidth);

				cuda.SetParameter(threshold, IntPtr.Size*2, (uint)frameHeight);

				cuda.SetParameterSize(threshold, (uint)IntPtr.Size * 3);

				cuda.Launch(threshold, block_size_x, block_size_y);

				float[] newPixels = new float[frameSize];

				cuda.CopyDeviceToHost<float>(deviceInData, newPixels);

				cuda.Free(deviceInData);

				//cuda.UnloadModule(module);

				//cuda.Dispose();

				//cuda = null;

			}

			catch (Exception ex)

			{

				Console.WriteLine(ex);

			}		  

		}

	}

}
2

I’m doing all my CUDA development with a .NET wrapper, so I wish I could help…but I’ve written my own P/Invoke interface to the driver (instead of using the GASS interface), so I really can’t say what the problem is unless I see their source code (which is closed).

Here’s one thing to try…I’ve written a little piece of code that defines a singleton class that handles all the CUDA stuff for my program. This way, even if I instantiate the class in various parts of my interface program, there is only one instance of the ‘real’ CUDA-handler class that ever gets created. This keeps the program from trying to initialize CUDA multiple times, adding extra contexts, etc.

Just for the sake of testing, you could try making your class into a static class, and put the initialization code + code to load data + code to call the module all into one static method, and call that. If it works, then you’ll know it’s a problem with your program, and not the GASS interface.