Lock-Free Queues in Multithreaded Agents

Contention is the enemy

Once several scanner threads contend for the same mutex, throughput collapses and tail latency explodes. A single-producer, multi-consumer queue built on atomic operations removes that contention entirely.

Back-pressure, not blocking

The queue applies back-pressure by bounding its size. Producers that outrun consumers drop into a sampled mode rather than stalling the callback that the operating system is waiting on.

Measuring the win

Profiling before and after the change is the only honest way to claim an improvement. Instrument the queue depth alongside CPU time and watch both move together.