To control GPU threads use the standard play, pause, and breakpoints controls. They are all applicable to GPU kernels.
However, because GPUs have different execution models to CPUs, there are a few behavioral differences that are described below.
GPU breakpoints can be set in the same way as other breakpoints. See Set breakpoints.
Where a kernel pauses at a breakpoint, the currently selected GPU thread will be changed if the previously selected thread is no longer 'alive'.
For more information about NVIDIA GPU breakpoint handling, see NVIDIA GPU Breakpoints.
For more information about AMD GPU breakpoints handling, see AMD GPU Breakpoints.
The GPU execution model is noticeably different to that of the host CPU. In the context of stepping operations, that is, step in, step over, or step out, there are critical differences to note.
The smallest execution unit on a NVIDIA GPU is a warp, which on current GPUs is 32 threads. All threads in a warp execute in lockstep, which means that you cannot step each thread individually. All active threads in the warp execute step at the same time.
It is not currently possible to step over or step out of inlined GPU functions.
Note
NVIDIA GPU functions are often inlined by the compiler. This can be avoided
(dependent on hardware) by specifying the __noinline__ keyword in your
function declaration.