Insufficient worker count for moderate concurrent usage causes request queueing

Configuration with only 2 workers and 4 threads (8 total concurrent slots) is insufficient for applications experiencing moderate concurrent usage or with common 800ms callback latencies. Once all 8 slots are occupied, additional requests queue until a worker becomes available, causing user-visible delays.

For CPU-bound tasks, increase worker count using formula (2 * CPU_cores) + 1. For 4-core machine, use 5-9 workers. For I/O-bound tasks, increase thread count to 8-16 or switch to gevent workers which can handle higher concurrency per worker. Note: Increasing synchronous workers increases RAM consumption dramatically; gevent is more resource-efficient.