Abstract: A physically distributed cache memory system includes an interconnection network, first level cache memory slices, and second level cache memory slices. The first level cache memory slices are coupled to the interconnection network to generate tagged ordered store requests. Each tagged ordered store requests has a tag including requester identification and a store sequence token. The second level cache memory slices are coupled to the interconnection network to execute ordered store requests in-order across the physically distributed cache memory system in response to each tag of the tagged ordered store requests.

Abstract: Each processor in a distributed shared memory system has an associated memory and a coherence directory. The processor that controls a memory is the Home processor. Under certain conditions, another processor may obtain exclusive control of a data block by issuing a Load Lock instruction, and obtaining a writeable copy of the data block that is stored in the cache of the Owner processor. If the Owner processor does not complete operations on the writeable copy of the data prior to the time that the data block is displaced from the cache, it issues a Victim To Shared message, thereby indicating to the Home processor that it should remain a sharer of the data block. In the event that another processor seeks exclusive rights to the same data block, the Home processor issues an Invalidate message to the Owner processor.

Abstract: A method and an apparatus to reduce network utilization for source-based snoopy cache coherent protocols have been disclosed. In one embodiment, the method includes receiving at a first processor an invalidating snoop with respect to a physical address of a portion of a memory in a multiprocessor system from a second processor, checking whether a cache of the first processor stores a copy of data associated with the physical address, and recording an identification (ID) of the second processor if the cache of the first processor stores the copy of data associated with the physical address. Other embodiments have been claimed and described.

Abstract: A multi-threaded processor is configured to detect excepted instructions from a first program, and to stop fetching younger instructions from that same program, to thereby conserve system resources that can be used by other programs. Each fetched program instruction has an associated status bit, which is set if the instruction excepts. Each excepting instruction is logged in an exception logging unit, which causes the associated status bit to be set. Each program has an associated in-flight vector table that tracks the instructions that have been fetched for that program. The status bits are compared with the in-flight vector table to identify the program that is associated with an excepted instruction. That program is then disabled, thereby preventing further fetching of instructions for that program until the excepted instruction clears.

Abstract: An exception handler for a processor is split into two functional units to permit exceptions to be classified into two categories. The first category of exceptions includes performance critical excepted instructions, while the second category includes non-performance critical excepted instructions. The performance critical exceptions are routed to a speculative exception handler, which resolves the exceptions speculatively, even though the excepted instruction may lie in a speculative path of the program flow. The non-performance critical exceptions are routed to a non-speculative exception handler that only resolves exceptions when the excepted instruction is certain to execute in an actual path of the program flow.

Abstract: Each processor in a distributed shared memory system has an associated memory and a coherence directory. The processor that controls a memory is the Home processor. Under certain conditions, another processor may obtain exclusive control of a data block by issuing a Load Lock instruction, and obtaining a writeable copy of the data block that is stored in the cache of the Owner processor. If the Owner processor does not complete operations on the writeable copy of the data prior to the time that the data block is displaced from the cache, it issues a Victim To Shared message, thereby indicating to the Home processor that it should remain a sharer of the data block. In the event that another processor seeks exclusive rights to the same data block, the Home processor issues an Invalidate message to the Owner processor.

Abstract: A multi-threaded processor is configured to detect excepted instructions from a first program, and to stop fetching younger instructions from that same program, to thereby conserve system resources that can be used by other programs. Each fetched program instruction has an associated status bit, which is set if the instruction excepts. Each excepting instruction is logged in an exception logging unit, which causes the associated status bit to be set. Each program has an associated in-flight vector table that tracks the instructions that have been fetched for that program. The status bits are compared with the in-flight vector table to identify the program that is associated with an excepted instruction. That program is then disabled, thereby preventing further fetching of instructions for that program until the excepted instruction clears.

Abstract: An exception handler for a processor is split into two functional units to permit exceptions to be classified into two categories. The first category of exceptions includes performance critical excepted instructions, while the second category includes non-performance critical excepted instructions. The performance critical exceptions are routed to a speculative exception handler, which resolves the exceptions speculatively, even though the excepted instruction may lie in a speculative path of the program flow. The non-performance critical exceptions are routed to a non-speculative exception handler that only resolves exceptions when the excepted instruction is certain to execute in an actual path of the program flow.