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openclgpgpunvidia
user2654900
user2654900

Reputation: 1

Nvidia's openCL work-group scheduling policy

I'm fairly new to openCL and GPGPU programming and would like to clarify something: Do work-groups interleave like warps within a work-group on a SM of Nvidia card? Or they are always serialized, meaning one work-group has to retire before the next one comes in?

thanks

Eugene

Upvotes: 0

Views: 175

Answers (1)

DarkZeros
DarkZeros

Reputation: 8410

You are taking the wrong approach. You simply can't known how they are going to be scheduled.

In fact this is KEY element in the parallel aproach, that you can run millions of threads with little needs of sync between them. If you need to know how to sync them, then it would be a hell.

Additionally, it is not that a given device runs always the work groups in the same order. The order differes each launch. The amount of parallel workgroups varies also, so it can be groups of 4 thengroups of 5 (for example).

Take this into account when designing, you should completely detach each work-item to work on it's own.

Upvotes: 1

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