203 results about "Symmetric multiprocessing" patented technology

A processor architecture containing multiple closely coupled processors in a form of symmetric multiprocessing system is provided. The special coupling mechanism allows it to speculatively execute multiple threads in parallel very efficiently. Generally, the operating system is responsible for scheduling various threads of execution among the available processors in a multiprocessor system. One problem with parallel multithreading is that the overhead involved in scheduling the threads for execution by the operating system is such that shorter segments of code cannot efficiently take advantage of parallel multithreading. Consequently, potential performance gains from parallel multithreading are not attainable. Additional circuitry is included in a form of symmetrical multiprocessing system which enables the scheduling and speculative execution of multiple threads on multiple processors without the involvement and inherent overhead of the operating system. Advantageously, parallel multithreaded execution is more efficient and performance may be improved.

Methods and systems for enhanced computer performance improve software application execution in a computer system using, for example, a symmetrical multi-processing operating system including OS kernel services in kernel space of main memory, by using groups of related applications isolated areas in user space, such as containers, and using a reduced set of application group specific set of resource management services stored with each application group in user space, rather than the OS kernel facilities in kernel space, to manage shared resources during execution of an application, process or thread from that group. The reduced sets of resource management services may be optimized for the group stored therewith. Execution of each group may be exclusive to a different core of a multi-core processor and multiple groups may therefore execute separately and simultaneously on the different cores.

Methods and apparatus are provided for eliminating hot spots on processor chips in a symmetric multiprocessor (SMP) computer system. Some operations, in particular, floating point multiply/add, repetitively utilize portions of a processor chip to the point that the average power of the affected portions exceeds cooling capabilities. The localized temperature of the affected portions can then exceed design limits. The current invention determines when a hot spot occurs and task swaps the task to another processor prior to the localized temperature becoming too hot. Moving of tasks to processors that have data affinity with the processor reporting a hot spot is considered. Further considerations include prioritizing unused processors and those processors that have not recently reported a hot spot.

A computer implemented method, apparatus, and computer program product for managing symmetric multiprocessor interconnects. The process identifies functional communication connections between each processor in a plurality of processors on a multiprocessor to form identified functional communication connections. The process maps every functional communication connection between any two processors in the plurality of processors, based on the identified functional communication connections, to form an interconnect matrix. The process creates a path map using the interconnect matrix. The path map comprises a sequence of communication connections between the plurality of processors. The process initializes the plurality of processors using the path map.

A facility is provided for communicating among processes in a symmetric multi-processing (SMP) cluster environment wherein at least some SMP nodes of the SMP cluster include multiple processes. The facility includes transferring intra-nodal at an SMP node messages of a collective communication among processes employing a shared memory of the SMP node; and responsive to the intra-nodal transferring, concurrently transferring inter-nodal multiple messages of the collective communication from n SMP node(s) to m other SMP node(s), wherein at least one of n or m is greater than one. The concurrently transferring is performed by multiple processes of at least one of the n SMP node(s) or the m other SMP node(s). More particularly, the facility includes concurrently transferring inter-nodal the multiple messages from one of: one SMP node to multiple other SMP nodes, multiple SMP nodes to one other SMP node, or multiple SMP nodes to multiple other SMP nodes.

A wake-and-go mechanism is provided for a data processing system. The wake-and-go mechanism recognizes a programming idiom, specialized instruction, operating system call, or application programming interface call that indicates that a thread is waiting for an event. The wake-and-go mechanism updates a wake-and-go array with a target address, expected data value, and comparison type associated with the event. The thread then goes to sleep until the event occurs. The wake-and-go array may be a content addressable memory (CAM). When a transaction appears on the symmetric multiprocessing (SMP) fabric that modifies the value at a target address in the CAM, logic associated with the CAM performs a comparison based on the data value being written, expected data value, and comparison type.

A packetized I/O link such as the HyperTransport protocol is adapted to transport memory coherency transactions over the link to support cache coherency in distributed shared memory systems. The I/O link protocol is adapted to include additional virtual channels that can carry command packets for coherency transactions over the link in a format that is acceptable to the I/O protocol. The coherency transactions support cache coherency between processing nodes interconnected by the link. Each processing node may include processing resources that themselves share memory, such as symmetrical multiprocessor configuration. In this case, coherency will have to be maintained both at the intranode level as well as the internode level. A remote line directory is maintained by each processing node so that it can track the state and location of all of the lines from its local memory that have been provided to other remote nodes. A node controller initiates transactions over the link in response to local transactions initiated within itself, and initiates transactions over the link based on local transactions initiated within itself. Flow control is provided for each of the coherency virtual channels either by software through credits or through a buffer free command packet that is sent to a source node by a target node indicating the availability of virtual channel buffering for that channel.

A method and apparatus for managing cache injection in a multiprocessor system reduces processing time associated with direct memory access transfers in a symmetrical multiprocessor (SMP) or a non-uniform memory access (NUMA) multiprocessor environment. The method and apparatus either detect the target processor for DMA completion or direct processing of DMA completion to a particular processor, thereby enabling cache injection to a cache that is coupled with processor that executes the DMA completion routine processing the data injected into the cache. The target processor may be identified by determining the processor handling the interrupt that occurs on completion of the DMA transfer. Alternatively or in conjunction with target processor identification, an interrupt handler may queue a deferred procedure call to the target processor to process the transferred data. In NUMA multiprocessor systems, the completing processor/target memory is chosen for accessibility of the target memory to the processor and associated cache.

A shared memory system for symmetric multiprocessing systems including a plurality of physical memory locations in which the locations are either allocated to one node of a plurality of processing nodes, equally distributed among the processing nodes, or unequally distributed among the processing nodes. The memory locations are configured to be accessed by the plurality of processing nodes by mapping all memory locations into a plurality of address partitions within a hierarchy bus. The memory locations are addressed by a plurality of address aliases within the bus while the properties of the address partitions are employed to control transaction access generated in the processing nodes to memory locations allocated locally and globally within the processing nodes.

A method, apparatus and program for booting a non-uniform-memory-access (NUMA) machine are provided. The invention comprises configuring a plurality of standalone, symmetrical multiprocessing (SMP) systems to operate within a NUMA system. A master processor is selected within each SMP; the other processors in the SMP are designated as NUMA slave processors. A NUMA master processor is then chosen from the SMP master processors; the other SMP master processors are designated as NUMA slave processors. A unique NUMA ID is assigned to each SMP that will be part of the NUMA system. The SMPs are then booted in NUMA mode in one-pass with memory coherency established right at the beginning of the execution of the system firmware.

A system-on-chip includes a symmetric multi-processor including a plurality of cores, each configured to operate in a high performance operating mode and a low performance operating mode. The system-on-chip further includes a clock management unit configured to provide an operating clock signal to the symmetric multi-processor, a state management unit configured to monitor operating states of the cores, a temperature management unit configured to monitor a temperature of the symmetric multi-processor, and a symmetric multi-processor control unit configured to determine the operating clock signal and the operating states of the cores based on a workload of the symmetric multi-processor. The symmetric multi-processor control unit is further configured to differentially determine a maximum operating clock frequency for the cores based on the temperature and the operating states of the cores, which indicate a quantity of cores that are currently in operation.

A multiprocessing system is disclosed. The system includes a multithreading microprocessor having a plurality of thread contexts (TCs), a translation lookaside buffer (TLB) shared by the plurality of TCs, and an instruction scheduler, coupled to the plurality of TCs, configured to dispatch to execution units, in a multithreaded fashion, instructions of threads executing on the plurality of TCs. The system also includes a multiprocessor operating system (OS), configured to schedule execution of the threads on the plurality of TCs, wherein a thread of the threads executing on one of the plurality of TCs is configured to update the shared TLB, and prior to updating the TLB to disable interrupts, to prevent the OS from unscheduling the TLB-updating thread from executing on the plurality of TCs, and disable the instruction scheduler from dispatching instructions from any of the plurality of TCs except from the one of the plurality of TCs on which the TLB-updating thread is executing.