Abstract: An apparatus for bypassing an invalidate search of a lookaside buffer includes a filter circuit that directs an invalidate command to a LPID/PID filter of an MMU of a processor and searches for an identifier targeted by the invalidate command. The MMU is external to cores of the processor. The apparatus includes an LPID/PID miss circuit that bypasses searching the lookaside buffer for addresses targeted by the invalidate command and returns a notification that the invalidate command did not identify the identifier targeted by the invalidate command in response to the filter circuit determining that the identifier targeted by the invalidate command is not stored in the LPID/PID filter.

Abstract: An apparatus for bypassing an invalidate search of a lookaside buffer includes a filter circuit that directs an invalidate command to a LPID/PID filter of an MMU of a processor and searches for an identifier targeted by the invalidate command. The MMU is external to cores of the processor. The apparatus includes an LPID/PID miss circuit that bypasses searching the lookaside buffer for addresses targeted by the invalidate command and returns a notification that the invalidate command did not identify the identifier targeted by the invalidate command in response to the filter circuit determining that the identifier targeted by the invalidate command is not stored in the LPID/PID filter.

Abstract: An SMT system is designed to allow software alteration of thread priority. In one case, the system signals a change in a thread priority based on the state of instruction execution and in particular when the instruction has completed execution. To alter the priority of a thread, the software uses a special form of a “no operation” (NOP) instruction (hereafter termed thread priority NOP). When the thread priority NOP is dispatched, its special NOP is decoded in the decode unit of the IDU into an operation that writes a special code into the completion table for the thread priority NOP. A “trouble” bit is also set in the completion table that indicates which instruction group contains the thread priority NOP. The trouble bit indicates that special processing is required after instruction completion. The thread priority instruction is processed after completion using the special code to change a thread's priority.

Abstract: A processor supports logical partitioning of hardware resources including real address spaces of a computer system. An ultra-privileged supervisor process, called a hypervisor, regulates the logical partitions and can dynamically re-allocate resources. Preferably, the processor supports hardware multithreading, each thread independently capable of being in either hypervisor, supervisor, or problem state, and is capable of entering hypervisor state only upon occurrence of certain pre-defined events. A logical partition identifier is stored in a processor register, and can be altered by the processor only when in hypervisor state. Certain bus communications contain a logical partition identifier tag, and the processor ignores such communications if the tag does not match its own logical partition identifier in its register.