SIMT (single instruction, multiple threads)
Beginner
A way of running a program where a group of workers all do the same step at the same moment, each on its own piece of data.
Novice
The GPU execution model. You write code for one thread; the hardware groups threads into warps and issues each instruction once for the whole group, each thread using its own data and registers.
Expert
Like SIMD in hardware, but the ISA describes one scalar thread and the hardware handles grouping and divergence with active masks. Correctness ignores warp width; performance doesn’t.
Explained in SIMT and GPUs (Architectures).
See also: Warp (wavefront), SIMD (single instruction, multiple data), Branch divergence.