Goal - Encourage Python developers to understand C extensions by sharing gRPC Python’s practice, and advocate the adoption of AsyncIO. Prerequisite - Understand thread vs. process; - Interested in asynchronous programming. gRPC Brief - What’s gRPC Core? And what is gRPC Python? Cython To The Rescue - Why we picked Cython among all other available tools (e.g., pybind11, ctypes) - Debuggability: pdb & gdb The GIL Friction - How to delegate work to C extension - How to make multithreading work AsyncIO Topic - Not blocking the loop, the main headache. - Non-blocking I/O solution 1: replacing C libraries’ I/O operations - Non-blocking I/O solution 2: dedicated background poller thread - Performance improvement (10k -> 20k for client, 4k -> 16k for server) Migration to AsyncIO - Tolerate multithreading and AsyncIO in the same application - Make both API co-existable in the same application