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Simulators

Race condition simulator

Two threads each add 1 to a shared counter, one machine instruction (load, add, store) at a time, in the order you choose. Pick an order that loses an update and see the counter end at 1 instead of 2.

The simulator

Race condition simulator: how to use it

Turn the lock on and the second thread must wait until the first has finished its critical section, so no order can lose an update.

Lessons that use it

  • Threads and race conditions (Operating Systems)Threads share a process's memory but each has its own stack. Why that makes count++ unsafe: a race condition you can cause yourself, step by step.
  • Synchronization: locks and semaphores (Operating Systems)The critical-section problem and its three rules, Peterson's solution, hardware atomic instructions, mutex locks, semaphores, and the producer-consumer, readers-writers and dining-philosophers problems.

See also