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Buffer vs. Image performance

Question asked by boxerab on Aug 2, 2014
Latest reply on Aug 12, 2014 by dipak

Can anyone comment on their experience using buffer/local memory as opposed to images ?

 

It seems that the standard way of doing image convolution is to:

 

1) read from system memory into global buffer

2) break up the global buffer into 2D blocks,

3) do a coalesced read of each block into local buffer

4) perform calculations

5) write back to global buffer.

 

With opencl images, there is no need to use local memory: simply read from image A,

perform calculations, then write to image B.  (image A cannot be read /write at the moment).

Care must be taken to avoid bank conflicts in the local memory.

 

On AMD hardware, which is faster?  Certainly, images make things simpler: no need to worry

about boundaries or local memory buffer.  But, am I deluding myself in thinking that images

are better than global/local scheme, for image convolutions?

 

Thanks!

 

Aaron

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