[Rtk-users] GPUs testing

[Simon Rit]

Hi,
Thanks for sharing your results.
RTK uses CUFFT for the ramp filtering which does its own blocks/grid
management. For backprojection, it's pretty simple, see
https://github.com/SimonRit/RTK/blob/master/src/rtkCudaFDKBackProjectionImageFilter.cu#L198
mostly hardcoded, independent of the number of CUDA cores and could be
optimized. There is one compilation parameter that you can try to change to
see if that speeds up the computation, that is the cmake variable
RTK_CUDA_PROJECTIONS_SLAB_SIZE which controls how many projections are
backprojected simultaneously.
We currently currently don't propose any way to use multiple GPUs.
Please keep us posted if you continue to do some tests. In particular, I
advise turning on RTK_TIME_EACH_FILTER in cmake so that you get a report
with -v option in applications on how much time your program spent in each
filter.
Best regards,
Simon

On Wed, Jul 18, 2018 at 6:48 PM, Elena Padovani <elenapadovani.lk at gmail.com>
wrote:

> Hi RTK-users,
>
> I compiled RTK with CUDA and tried to setup a benchmark to analyze the
> performances trend of the GPUs when using the CUDA-FDK reconstruction
> filter. Precisely, when reconstructing the same volume from the same
> data-set on NVS510 GTX860M and GTX970M i got results consistent with the
> number of GPUs cuda cores. Indeed, when setting up this benchmark i was
> expecting a reduction in the reconstruction time with the increase of
> cuda cores(at least until the dimension of the reconstructed volume was not
> the actual bottleneck). However, when testing it on a Tesla P100 i got
> performances comparable to the GTX860M. Would you expect such a result?
>
> Unfortunately i am new to CUDA and i was wondering if any of you could
> help me figuring this out.
> How does rtk with CUDA manage the number of blocks/grid dimension ?
> Is the number of blocks/grid dimension depedent on the GPU cuda cores?
> Is there a way to use multiple GPUs?
>
> The test was carried with the following data:
> - 360 projections
> - reconstructed volume 600x700x800 px
>
> Thank you in advance
> Kind regards
>
> Elena
>
>
> _______________________________________________
> Rtk-users mailing list
> Rtk-users at public.kitware.com
> https://public.kitware.com/mailman/listinfo/rtk-users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://public.kitware.com/pipermail/rtk-users/attachments/20180718/c3a7c4cc/attachment.html>