What is the purpose of "memory barriers" (fences) in multi-core/multi-threaded programming on modern architectures with relaxed memory models?
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Incorrect.
The correct answer is A) They enforce ordering constraints on memory operations (loads/stores), preventing the CPU or compiler from reordering certain accesses across the barrier, necessary for correct synchronization on architectures that allow reordering for performance
Correct Answer
They enforce ordering constraints on memory operations (loads/stores), preventing the CPU or compiler from reordering certain accesses across the barrier, necessary for correct synchronization on architectures that allow reordering for performance
Architectures with relaxed memory models (allowing reordering of loads/stores for performance) require explicit memory barriers/fences at points where ordering matters (e.g., implementing locks), ensuring all cores observe a consistent, expected ordering of operations.