[Rtk-users] Cuda and RTK

[Fredrik Hellman]

Hi,

Thanks Simon! I see.

I am writing a CUDA application of which where RTK and ITK will be parts,
and I want to know how RTK CUDA cooperates with the CUDA functionality I
already have in my application. I have found some behaviors that would be
nice to be able to control/change or at least understand the design of:

* Context handling. It appears the CUDA context manager keeps track of
contexts and also can switch between them, I think I would like to be able
to control this on a higher level. I can see situations where multple
libraries compete with the control of contexts.
* Streams. It would be nice to be able to perform data transfer between
CPU/GPU in parallell with computations, but that requires that another
stream than the default stream is used, since the default stream is always
synchronous.
* Memory allocations. When CUDA memory is allocated and deallocated, it
implicitly synchronizes all operations on the GPU (
https://docs.nvidia.com/cuda/cuda-c-programming-guide/#implicit-synchronization).
It would be good if one could either provide allocators/deallocates for a
memory pool which doesn't need to issue the actual allocation calls, but
get buffers from a pre allocated pool. Or find a a way to disable
reallocations (which sometimes can be very frequent in ITK, especially if
doing streaming).

Are these areas that the community would be interested in too? Has there
been any developments or discussions about this earlier?

Best regards,
Fredrik Hellman

On Tue, 30 Apr 2019 at 15:02, Simon Rit <simon.rit at creatis.insa-lyon.fr>
wrote:

> Hi,
> Everything you're saying is correct. This development was co-funded by the
> RTK consortium and Kitware and the goal was to transfer it to ITK. However,
> this has never occurred and at this stage, it is only maintained in RTK.
> Ideally, this could become an independent ITK module.
> Is it something you'd like/need?
> Cheers,
> Simon
>
> On Tue, Apr 30, 2019 at 2:58 PM Fredrik Hellman <fredrik.hellman at gmail.com>
> wrote:
>
>> Hi all,
>>
>> I have a question about the the code that deals with cuda within RTK.
>>
>> RTK uses itk cuda image, the itk data manager, and itk context manager
>> (but not itk kernel manager so much?) to handle cuda data. Is this
>> maintained as part of RTK or is it maintained somewhere else and only used
>> in RTK? Now when RTK becomes closer to ITK, what will happen to that code?
>>
>> Best regards,
>> Fredrik
>>
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>
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