Segment 24
This sub-session completed the Phase 8 dual-worker GPU interlock implementation, which eliminated GPU idle gaps by narrowing the static mutex in generate_groth16_proofs_c to cover only CUDA kernel regions, allowing two GPU workers per device to interleave CPU preprocessing with GPU execution. The change spanned 7 files including C++ CUDA kernel refactoring, FFI plumbing through supraseal-c2, bellperson, and pipeline.rs, and engine support for configurable gpu_workers_per_device. Benchmarking showed 100% single-proof GPU efficiency and 13.2-17.2% multi-proof throughput improvement (44.0-49.5s/proof vs 50.7-59.8s for Phase 7). Following implementation, the assistant conducted a systematic sweep of partition_workers values (10, 12, 15, 18, 20) to find the optimal setting, discovering that pw=10 and pw=12 tied for best throughput at 43.5s/proof, with higher values regressing due to CPU contention. The sweep was fully completed and the daemon shut down, providing empirical guidance for production configuration.