The Scalability of Spinlocks vs Sleep-locks.

Senior-level concurrency addresses the intersection of software logic, CPU architecture, and memory consistency models to achieve extreme throughput and low latency.

At this stage, we are dealing with CPU Cache lines (64 bytes), instruction reordering by the hardware, and the specific cost of atomic primitives. We look at Lock-Free algorithms that use CAS loops instead of OS-level context switching, and we worry about things like the ABA problem or Memory Reclamation (Hazard Pointers).