[Starpu-devel] initialised SCRATCH buffer

[Xavier Lacoste <xavier.lacoste@inria.fr>]

Hello,

I would like to know if it was possible to initialize a SCRATCH buffer 
using the a function of the codelets parameters ?

I have a CUDA codelet which as to perform a GEMM with one one matrix and 
a sub-bloc of this column and use the product to update an other matrix 
in several sub-blocs.
So I have one GEMM and several AXPY (one AXPY per column of each 
sub-bloc under the bloc used for the product).
I understood that the number of CUDA calls explain the poor perfomances 
of my CUDA codelet.

Thus I wrote a CUDA kernel for sparse GEMM based on MAGMA Tesla CUDA kernel.
I had to the MAGMA kernel 2 arrays containing the indexes of each bloc 
of the product and the corresponding indexes where I have to write in 
the destination buffer.

My problem is now I want to use this kernel with StarPU in PaStiX but I 
don't want to allocate one buffer by task.
I would like StarPU to build the array using a function of the codelet 
arguments at the same time he moves data to the executing device.

Am I clear in my explanation ?
Is this the good way to do ?
Is this already available in StarPU ?
If not, can this feature be added to StarPU ?

Thanks,

Xavier Lacoste.