Translations:CUDA tutorial/4/en

CUDA block-threading model where threads are organized into blocks while blocks are further organized into grid.

Given a very large number of threads - in order to achieve massive parallelism one has to use all the threads possible - in a CUDA kernel, one needs to organize them somehow. In CUDA, all the threads are structured in threading blocks, the blocks are further organized into grids, as shown in the accompanying figure. In distributing the threads we must make sure that the following conditions are satisfied:

• threads within a block cooperate via the shared memory
• threads in different blocks can not cooperate

In this model the threads within a block work on the same set of instructions (but perhaps with different data sets) and exchange data between each other via shared memory. Threads in other blocks do the same thing (see the figure).

Threads within a block intercommunicate via shared memory.