Re: [Starpu-devel] Error - No worker may execute this task

[Sylvain HENRY <sylvain.henry@inria.fr>]

Hi,

As Samuel wrote, d_src is a cl_mem. If you would like to use images and samplers, you have to follow this pattern:
1) allocate d_tex_src and d_tex_dst using clCreateImage2D without specifying the host_ptr
2) use clEnqueueCopyImageToBuffer to copy from d_src (StarPU managed OpenCL buffer) to d_tex_src
3) clEnqueueNDRangeKernel with d_tex_src and d_tex_dst as parameters
4) use clEnqueueCopyBufferToImage to copy from d_tex_dst to d_dst (StarPU managed OpenCL buffer)
5) Free d_tex_src and d_tex_dst

Note that you don't need clEnqueueWriteImage at all or any other host->device transfer mechanism, only two device->device copies. However I assumed that d_dst was an image too. If that's not the case, you don't need d_tex_dst and the last copy (4).

Do not forget to use dependencies between copies and kernel execution as the queue may not be executed in order.

Hope that helps.

Cheers
Sylvain


Le 29/11/2011 15:59, Samuel Thibault a écrit :

One odd thing is this:

cl_mem d_tex = clCreateImage2D(context, CL_MEM_READ_ONLY, &format, width, height, 0 ,(void *) d_src, &err);

as examplified in the documentation, what STARPU_MATRIX_GET_PTR()
returns is a cl_mem, i.e. a device pointer, not a host pointer. Why do
you want to create an image and copy data in it actually? StarPU already
handles all CPU/GPU transfers for you, you just need to use the d_src
and d_dst buffers.

Samuel

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