CODEWITHSUNDEEP
cuda
user570593
user570593

Reputation: 3520

CUDA 2D, 3D thread blocks

According to http://en.wikipedia.org/wiki/CUDA, Maximum x- or y-dimension of a block 1024 Maximum z-dimension of a block 64

Does it mean we can have 1024 x 1024 x 64 threads per block or we can have a maximum of 1024+64 threads in a block?

Upvotes: 2

Views: 1553

Answers (1)

talonmies
talonmies

Reputation: 72372

The limits are defined in Append G of recent programming guides, but the answer is either 512 or 1024 threads per block total, depending on whether you have a Fermi, or older card.

So for Fermi

blockDim.x * blockDim.y * blockDim.z <= 1024

and for GT200/G90/G80/Ion:

blockDim.x * blockDim.y * blockDim.z <= 512

Note the are other resource limits (shared memory and registers) which may require block sizes to be be smaller than the limits, depending on code complexity. This is also discussed at some length in the programming guide.

Upvotes: 5

Related Questions