CODEWITHSUNDEEP
cuda
meJustAndrew
meJustAndrew

Reputation: 6623

Is there a minimum block size in cuda?

I can find multiple articles describing the upper bounds of a block size, but I was not able to find if a block should have a minimum number of threads.

Also, if the block can have fewer threads than 32, then what happens to the rest of the threads in the corresponding warp since a block is composed of warps that are 32 threads long?

Sorry if the answer is obvious.

Upvotes: 3

Views: 1245

Answers (1)

nglee
nglee

Reputation: 1933

Question1. Is there a minimum block size?

1.

Question2. What happens to the rest of the threads in the corresponding warp if the block has fewer than 32 threads?

Rest of them are inactive. They don't fetch operands and they don't write output. They don't execute something else, though. They still spend time in the instructions other active threads are executing. See page 10 of this.

Upvotes: 6

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