Resource Contention

Without coordination, two threads writing to the same memory location produce a race condition where the final value depends on the unpredictable order of execution. Well-defined protocols such as locks, signals, and message queues are required to ensure shared data is read and written consistently. Resource contention occurs when two or more threads attempt to use the same resource at the same time. A single bottleneck resource forces threads to queue and wait, reducing the throughput gains that concurrency was intended to deliver. Without coordination, two threads accessing the same resource simultaneously can corrupt data or produce undefined behavior.