CODEWITHSUNDEEP
openglopencl
fho
fho

Reputation: 6798

Should i orphan OpenCL buffers?

In OpenGL it is a common practice to orphan buffers that are used frequently. Ideally the drivers notices that a buffer of the same size is requested and if possible returns the old buffer if it is not needed anymore. The buffer only allocates new memory when the old buffer is still in use and can't be reused.

In OpenCL (on NVIDIA Hardware using the latest developer drivers) i am not sure about this technic. I got a 256kB buffer that is handled by the c++ wrapper refcounting which i reallocate frequently. Most of the time this works fine but in some cases OpenCL throws a CL_OUT_OF_MEMORY error while allocating a new buffer.

Do you think that i should switch my approach (e.g. using a constant number of buffers)? Or should i investigate in an other possible cause for this problem?

Kind regards, Florian

Upvotes: 1

Views: 1410

Answers (1)

dietr
dietr

Reputation: 1238

OpenCL uses the C semantics for memory allocation and deallocation. As such, it will not automatically reuse buffers. You have to explicitly release a buffer and allocate a new buffer later. Alternatively, it seems to be a good practice to reuse buffers manually. Allocation can be a quite expensive operation.

Upvotes: 1

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