1. A method comprising: switching a first instruction execution thread to an active mode; while the first instruction execution thread is in the active mode, disabling the first instruction execution thread; and in response to disabling the first instruction thread, switching a second instruction execution thread to the active mode, wherein if the first instruction execution thread is disabled by the first instruction execution thread, switching the second instruction execution thread to the active mode comprises switching the second instruction execution thread such that no instruction corresponding to the first instruction execution thread is fetched and issued (i) subsequent to disabling the first instruction execution thread, and (ii) prior to switching the second instruction execution thread to the active mode, and wherein if the first instruction execution thread is disabled by the second instruction execution thread, switching the second instruction execution thread to the active mode comprises switching the second instruction execution thread such that an instruction corresponding to the first instruction execution thread is fetched and issued (i) subsequent to disabling the first instruction execution thread, and (ii) prior to switching the second instruction execution thread to the active mode.