Abstract: A processor contains a move engine and mapping engine that transparently reconfigure physical memory to accomplish addition, subtraction, or replacement of a memory module. A mapping engine register stores FROM and TO real addresses that enable the engines to virtualize the physical address of the memory module being reconfigured and provide the reconfiguration in real-time through the use of hardware functionality and not software. Using the FROM and TO real addresses to select a source and a target, the move engine copies the contents of the memory module to be removed or reconfigured into the remaining or inserted memory module. Then, the real address associated with the reconfigured memory module is re-assigned to the memory module receiving the copied contents, thereby creating a virtualized physical mapping from the addressable real address space being utilized by the operating system into a virtual physical address space.

Abstract: A computer system includes a home node and one or more remote nodes coupled by a node interconnect. The home node includes a local interconnect, a node controller coupled between the local interconnect and the node interconnect, a home system memory, a memory directory including a plurality of entries, and a memory controller coupled to the local interconnect, the home system memory and the memory directory. The memory directory includes a plurality of entries that each provide an indication of whether or not an associated data granule in the home system memory has a corresponding cache line held in at least one remote node. The memory controller includes demand invalidation circuitry that, responsive to a data request for a requested data granule in the home system memory, reads an associated entry in the memory directory and issues an invalidating command to at least one remote node holding a cache line corresponding to the requested data granule.

Abstract: A non-uniform memory access (NUMA) computer system includes at least one remote node and a home node coupled by a node interconnect. The home node contains a home system memory and a memory controller. In response to receipt of a data request from a remote node, the memory controller determines whether to grant exclusive or non-exclusive ownership of requested data specified in the data request by reference to history information indicative of prior data accesses originating in the remote node. The memory controller then transmits the requested data and an indication of exclusive or non-exclusive ownership to the remote node.

Abstract: Described is a data processing system and processor that provides full multiprocessor speculation by which all instructions subsequent to barrier operations in a instruction sequence are speculatively executed before the barrier operation completes on the system bus. The processor comprises a load/store unit (LSU) with a barrier operation (BOP) controller that permits load instructions subsequent to syncs in an instruction sequence to be speculatively issued prior to the return of the sync acknowledgment. Data returned is immediately forwarded to the processor's execution units. The returned data and results of subsequent operations are held temporarily in rename registers. A multiprocessor speculation flag is set in the corresponding rename registers to indicate that the value is “barrier” speculative. When a barrier acknowledge is received by the BOP controller, the flag(s) of the corresponding rename register(s) are reset.

Abstract: A method and system for speculatively pre-fetching data from a memory. A memory controller on a data bus “snoops” data requests put on the data bus by a bus control logic. Based on information in the header of the data request, such as transaction type, tag, transaction size, etc., a speculative pre-fetch is made to read data from the memory associated with the memory controller. If the speculative fetch turns out to be correct, then the memory controller makes an assumption that the pre-fetch was too conservative (non-speculative), and a pre-fetch for a next data request is performed at an earlier more speculative time. If the speculative fetch turns out to be incorrect, then the memory controller makes an assumption that the pre-fetch was too speculative (made early), and a pre-fetch for a next data request is performed at a later less speculative time.

Abstract: An apparatus for performing bus tracing with scalable bandwidth in a distributed memory symmetric multiprocesssor system is disclosed. The distributed memory symmetric multiprocessor system includes multiple processing units, each coupled to a memory module. Each of the processing units includes a memory controller and a bus trace macro (BTM) module. The memory controller is coupled to an interconnect for the symmetric multiprocessor system, and the BTM module is connected between the interconnect and the memory controller via two multiplexors. A subset of the BTM modules within the symmetric multiprocessor system is enabled for performing tracing is operations such that address transactions on the interconnect are divided among the subset of the BTM modules to be selectively and separately intercepted by each BTM module within the subset of the BTM modules.

Abstract: An apparatus for performing in-memory bus tracing in a data processing system having a distributed memory is disclosed. The apparatus includes a bus trace macro (BTM) module that can control the snoop traffic seen by one or more of the memory controllers in the data processing system and utilize a local memory attached to the memory controller for storing trace records. After the BTM module is enabled for tracing operations, the BTM module snoops transactions on the interconnect and packs information contained within these transactions into a block of data of a size that matches the write buffers within the memory controller.

Abstract: An apparatus for performing imprecise bus tracing in a distributed memory symmetric multiprocessor system is disclosed. The apparatus includes a bus trace macro (BTM) module that can control the snoop traffic seen by one or more of the memory controllers in the data processing system and utilize a local memory attached to the memory controller for storing trace records. After the BTM module is enabled for tracing operations, the BTM module snoops transactions on the interconnect and packs information contained within these transactions into a block of data of a size that matches the write buffers within the memory controller. In addition, the BTM module also includes a dropped record counter for counting the number of address transactions that were not converted to trace records because all the write buffers were completely full. After an occurence of the write buffers full condition, a time stamp trace record is inserted before a new trace record can be written.

Abstract: A method, system, and processor cache configuration that enables efficient retrieval of valid data in response to an invalidate cache miss at a local processor cache. A cache directory is provided a set of directional bits in addition to the coherency state bits and the address tag. The directional bits provide information that includes a processor cache identification (ID) and routing method. The processor cache ID indicates which processor's operation resulted in the cache line of the local processor changing to the invalidate (I) coherency state. The routing method indicates what transmission method to utilize to forward the cache line, from among a local system bus or a switch or broadcast mechanism. Processor/Cache directory logic provide responses to requests depending on the values of the directional bits.

Abstract: Disclosed herein are a data processing system and method of operating a data processing system that arbitrate between conflicting requests to modify data cached in a shared state and that protect ownership of the cache line granted during such arbitration until modification of the data is complete. The data processing system includes a plurality of agents coupled to an interconnect that supports pipelined transactions. While data associated with a target address are cached at a first agent among the plurality of agents in a shared state, the first agent issues a transaction on the interconnect. In response to snooping the transaction, a second agent provides a snoop response indicating that the second agent has a pending conflicting request and a coherency decision point provides a snoop response granting the first agent ownership of the data.

Abstract: Upon snooping an operation in which an intervention is permitted or required, an intervening cache may elect to source only that portion of a requested cache line which is actually required, rather than the entire cache line. For example, if the intervening cache determines that the requesting cache would likely be required to invalidate the cache line soon after receipt, less than the full cache line may be sourced to the requesting cache. The requesting cache will not cache less than a full cache line, but may forward the received data to the processor supported by the requesting cache. Data bus bandwidth utilization may therefore be reduced. Additionally, the need to subsequently invalidate the cache line within the requesting cache is avoided, together with the possibility that the requesting cache will retry an operation requiring invalidation of the cache line.

Abstract: A non-uniform memory access (NUMA) computer system and associated method of operation are disclosed. The NUMA computer system includes at least a remote node and a home node coupled to an interconnect. The remote node contains at least one processing unit coupled to a remote system memory, and the home node contains at least a home system memory. To reduce access latency for data from other nodes, a portion of the remote system memory is allocated as a remote memory cache containing data corresponding to data resident in the home system memory. In one embodiment, access bandwidth to the remote memory cache is increased by distributing the remote memory cache across multiple system memories in the remote node.

Abstract: A computer system includes a processing unit, a system memory, and a memory controller coupled to the processing unit and the system memory. According to the present invention, the memory controller accesses the system memory to obtain prefetch data and transmits the prefetch data to the processing unit in a prefetch write operation specifying the processing unit in a destination field. In one embodiment, the memory controller transmits the prefetch write operation in response to receipt of a prefetch hint from the processing unit, which may accompany a read-type request by the processing unit. This prefetch methodology may advantageously be implemented imprecisely, with the memory controller responding to the prefetch hint only if a prefetch queue is available and ignoring the prefetch hint otherwise. The processing unit may similarly ignore the prefetch write operation if no snoop queue is available.

Abstract: A non-uniform memory access (NUMA) computer system includes a first node and a second node coupled by a node interconnect. The second node includes a local interconnect, a node controller coupled between the local interconnect and the node interconnect, and a controller coupled to the local interconnect. In response to snooping an operation from the first node issued on the local interconnect by the node controller, the controller signals acceptance of responsibility for coherency management activities related to the operation in the second node, performs coherency management activities in the second node required by the operation, and thereafter provides notification of performance of the coherency management activities.

Abstract: A hardware managed virtual-to-physical address translation mechanism for a data processing system having no system memory is disclosed. The data processing system includes multiple processing units. The processing units have volatile cache memories operating in a virtual address space that is greater than a real address space. The processing units and the respective volatile memories are coupled to a storage controller operating in a physical address space. The processing units and the storage controller are coupled to a hard disk via an interconnect. The hard disk contains a virtual-to-physical translation table for translating a virtual address from one of said volatile cache memories to a physical disk address directed to a storage location in the hard disk without transitioning through a real address.

Abstract: An apparatus for influencing process scheduling in a data processing system capable of utilizing a virtual memory processing scheme is disclosed. The data processing system includes multiple processing units. The processing units have volatile cache memories operating in a virtual address space that is greater than a real address space. The processing units and the respective volatile memories are coupled to a storage controller operating in a physical address space that is equal to the virtual address space. The processing units and the storage controller are coupled to a hard disk via an interconnect. The storage controller, which is coupled to a physical memory cache, allows the mapping of a virtual address from one of the volatile cache memories to a physical disk address directed to a storage location within the hard disk without transitioning through a real address. The physical memory cache contains a subset of information within the hard disk.

Abstract: A data processing system having no system memory is disclosed. The data processing system includes multiple processing units. The processing units have volatile cache memories operating in a virtual address space that is greater than a real address space. The processing units and the respective volatile memories are coupled to a storage controller operating in a physical address space that is equal to the virtual address space. The processing units and the storage controller are coupled to a hard disk via an interconnect. The storage controller allows the mapping of a virtual address from one of the volatile cache memories to a physical disk address directed to a storage location within the hard disk without transitioning through a real address.

Abstract: An aliasing support for a data processing system having no system memory is disclosed. The data processing system includes multiple processing units. The processing units have volatile cache memories operating in a virtual address space that is greater than a real address space. The processing units and the respective volatile memories are coupled to a storage controller operating in a physical address space. The processing units and the storage controller are coupled to a hard disk via an interconnect. The processing units contains an aliasing table for associating at least two virtual addresses to a physical disk address directed to a storage location in the hard disk. The hard disk contains a virtual-to-physical translation table for translating a virtual address from one of said volatile cache memories to a physical disk address directed to a storage location in the hard disk without transitioning through a real address.

Abstract: A data processing system having no system memory is disclosed. The data processing system includes multiple processing units. The processing units have volatile cache memories operating in a virtual address space that is greater than a real address space. The processing units and the respective volatile memories are coupled to a storage controller operating in a physical address space that is equal to the virtual address space. The processing units and the storage controller are coupled to a hard disk via an interconnect. The storage controller, which is coupled to a physical memory cache, allows the mapping of a virtual address from one of the volatile cache memories to a physical disk address directed to a storage location within the hard disk without transitioning through a real address. The physical memory cache contains a subset of information within the hard disk.

Abstract: An access request for a data processing system having no system memory is disclosed. The data processing system includes multiple processing units. The processing units have volatile cache memories operating in a virtual address space that is greater than a real address space. The processing units and the respective volatile memories are coupled to a storage controller operating in a physical address space that is equal to the virtual address space. The processing units and the storage controller are coupled to a hard disk via an interconnect. The storage controller, which is coupled to a physical memory cache, allows the mapping of a virtual address from one of the volatile cache memories to a physical disk address directed to a storage location within the hard disk without transitioning through a real address. The physical memory cache contains a subset of information within the hard disk.