Simultaneous multithreading (SMT) allows processors to handle instructions from two threads at once, improving resource utilization. Intel’s hyper-threading is a form of SMT. Processors use techniques like pipelining and superscalar architecture to boost instruction throughput. SMT duplicates the processor’s architecture state to handle two threads simultaneously, sharing or duplicating resources as needed. Instructions are decoded into microinstructions and executed out of order to prevent resource wastage. However, sharing resources between logical processors can impact performance, especially if threads compete for cache access. Understanding SMT’s microarchitectural implementation is crucial for maximizing CPU core potential. Intel’s processors have made improvements to minimize resource wastage when only one thread is running.
https://blog.codingconfessions.com/p/simultaneous-multithreading