diff --git a/threading_performance_report.md b/threading_performance_report.md index 62e3f41..4c1aeb5 100644 --- a/threading_performance_report.md +++ b/threading_performance_report.md @@ -2,15 +2,17 @@ ## Summary -WeaselDB's /ok health check endpoint achieves 1M requests/second with 740ns of configurable CPU work per request through the 4-stage commit pipeline, while maintaining 0% CPU usage when idle. The configurable CPU work serves both as a health check (validating the full pipeline) and as a benchmarking tool for measuring per-request processing capacity. +WeaselDB's /ok health check endpoint achieves approximately 825k requests/second with 740ns of configurable CPU work per request through the 4-stage commit pipeline, while maintaining 0% CPU usage when idle. The configurable CPU work serves both as a health check (validating the full pipeline) and as a benchmarking tool for measuring per-request processing capacity. + +> **Note on historical numbers**: An earlier version of this report claimed 1.0M requests/second at 740ns serial CPU work. That measurement was made using a design that transferred unique ownership of connections through the pipeline. The current server-owned connection model adds per-request synchronization overhead that lowers the raw /ok throughput, but enables streaming endpoints such as `/v1/subscribe` and safer async response handling. ## Performance Metrics ### Throughput -- **1.0M requests/second** /ok health check endpoint (4-stage commit pipeline) +- **~825k requests/second** /ok health check endpoint (4-stage commit pipeline) - 8 I/O threads with 8 epoll instances -- Load tester used 12 network threads +- Load tester used 10 network threads - **0% CPU usage when idle** (optimized futex wake implementation) ### Threading Architecture @@ -24,10 +26,10 @@ WeaselDB's /ok health check endpoint achieves 1M requests/second with 740ns of c **Health Check Pipeline (/ok endpoint)**: -- **Throughput**: 1.0M requests/second +- **Throughput**: ~825k requests/second (sustained over a 30-second run) - **Configurable CPU work**: 740ns (4000 iterations, validated with nanobench) -- **Theoretical maximum CPU time**: 1000ns (1,000,000,000ns ÷ 1,000,000 req/s) -- **CPU work efficiency**: 74% (740ns ÷ 1000ns) +- **Theoretical maximum CPU time at this throughput**: ~1212ns (1,000,000,000ns ÷ 825,000 req/s) +- **CPU work efficiency**: ~61% (740ns ÷ 1212ns) - **Pipeline stages**: Sequence (noop) → Resolve (CPU work) → Persist (response) → Release (cleanup) - **CPU usage when idle**: 0% @@ -76,7 +78,7 @@ I/O Threads (8) → HttpHandler::on_batch_complete() → Commit Pipeline - Server: test_benchmark_config.toml with 8 io_threads, 8 epoll_instances - Configuration: `ok_resolve_iterations = 4000` (740ns CPU work) -- Load tester: targeting /ok endpoint +- Load tester: targeting /ok endpoint, 10 network threads, 8 connect threads, 2000 concurrent connections, 500 requests per connection - Benchmark validation: ./bench_cpu_work 4000 -- Build: ninja +- Build: ninja Release - Command: ./weaseldb --config test_benchmark_config.toml