CUDA Kernels

Understanding CUDA kernels and how to write efficient parallel code.

What is a CUDA Kernel?

A CUDA kernel is a function that runs on the GPU in parallel across many threads. Kernels are defined using the __global__ keyword and are launched using the <<<...>>> syntax.

Kernel Examples

Here are examples of different types of CUDA kernels:

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Kernel Launch Parameters

When launching a kernel, you specify:

  • Number of blocks in the grid
  • Number of threads per block
  • Amount of shared memory (optional)
  • CUDA stream (optional)

Kernel Optimization Tips

  • Choose appropriate block sizes for your GPU
  • Minimize divergent branching within warps
  • Use shared memory for frequently accessed data
  • Ensure coalesced memory access patterns
  • Balance occupancy and resource usage