Un co rre ct ed Pr oo f T Thread - Level Speculation

Definition  Thread-Level Speculation (TLS) refers to an environ ment where execution threads operate speculatively,  performing potentially unsafe operations, and tem porarily buffering the state they generate in a buffer or  cache. At a certain point, the operations of a thread are  declared to be correct or incorrect. If they are correct,  the thread commits, merging the state it generated with  the correct state of the program; if they are incorrect,  the thread is squashed and typically restarted from its  beginning. The term TLS is most often associated to  a scenario where the purpose is to execute a sequen tial application in parallel. In this case, the compiler or  the hardware breaks down the application into specu lative threads that execute in parallel. However, strictly  speaking, TLS can be applied to any environment where  threads are executed speculatively and can be squashed  and restarted. 