Abstract: A cache coherent data processing system includes at least first and second coherency domains each including at least one processing unit. The first coherency domain includes a first cache memory, and the second coherency domain includes a coherent second cache memory. The first cache memory within the first coherency domain of the data processing system holds a memory block in a storage location associated with an address tag and a coherency state field. The coherency state field is set to a state that indicates that the address tag is valid, that the storage location does not contain valid data, and that the memory block is likely cached only within the first coherency domain.

Abstract: A data processing system includes a plurality of processing units each having a respective point-to-point communication link with each of multiple others of the plurality of processing units but fewer than all of the plurality of processing units. Each of the plurality of processing units includes interconnect logic, coupled to each point-to-point communication link of that processing unit, that broadcasts requests received from one of the multiple others of the plurality of processing units to one or more of the plurality of processing units. The interconnect logic includes a partial response data structure including a plurality of entries each associating a partial response field with a plurality of flags respectively associated with each processing unit containing a snooper from which that processing unit will receive a partial response.

Abstract: A data processing system includes a plurality of processing units each having a respective point-to-point communication link with each of multiple others of the plurality of processing units but fewer than all of the plurality of processing units. Each of the plurality of processing units includes interconnect logic, coupled to each point-to-point communication link of that processing unit, that broadcasts operations received from one of the multiple others of the plurality of processing units to one or more of the plurality of processing units.

Abstract: A cache coherent data processing system includes at least first and second coherency domains coupled for communication. The first and second coherency domains each include a respective one of first and second cache memories. A master in the first coherency domain selects a scope of an initial broadcast of an operation from among a first scope including only the first coherency domain and a second scope including both the first and second coherency domains based, at least in part, upon a type of the operation. The master then performs an initial broadcast of the operation within the cache coherent data processing system utilizing the selected scope.

Abstract: A method, system and computer program product for handling write requests in a data processing system is disclosed. The method comprises receiving on an interconnect bus a first write request targeted to a first address and receiving on the interconnect bus a subsequent second write request targeted to a subsequent second address. The subsequent second write request is completed prior to completing the first write request, and, responsive to receiving a read request targeting the second address before the first write request has completed, data associated with the second address of the second write request is supplied only after the first write request completes.

Abstract: A method and apparatus for performing data prefetch in a multiprocessor system are disclosed. The multiprocessor system includes multiple processors, each having a cache memory. The cache memory is subdivided into multiple slices. A group of prefetch requests is initially issued by a requesting processor in the multiprocessor system. Each prefetch request is intended for one of the respective slices of the cache memory of the requesting processor. In response to the prefetch requests being missed in the cache memory of the requesting processor, the prefetch requests are merged into one combined prefetch request. The combined prefetch request is then sent to the cache memories of all the non-requesting processors within the multiprocessor system. In response to a combined clean response from the cache memories of all the non-requesting processors, data are then obtained for the combined prefetch request from a system memory.

Abstract: In a multiprocessor environment, by executing cache-inhibited reads or writes to registers, a scan communication is used to rapidly access registers inside and outside a chip originating the command. Cumbersome locking of the memory location may be thus avoided. Setting of busy latches at the outset virtually eliminates the chance of collisions, and status bits are set to inform the requesting core processor that a command is done and free of error, if that is the case.

Abstract: A method and system for enabling directed temperature/power management at the DIMM-level and/or DRAM-level utilizing intelligent scheduling of memory access operations received at the memory controller. Hot spots within the memory subsystem, caused by operating the DIMMs/DRAMs above predetermined/preset threshold power/temperature values for operating a DIMM and/or a DRAM, are avoided/controlled by logic within the memory controller. The memory controller logic throttles the number/frequency at which commands (read/write operations) are issued to the specific DIMM/DRAM based on feedback data received from the specific DIMM/DRAM reaching the preset threshold power usage value.

Abstract: A system and method of recovering from errors in a data processing system. The data processing system includes one or more processor cores coupled to one or more memory controllers. The one or more memory controllers include at least a first memory interface coupled to a first memory and at least a second memory interface coupled to a second memory. In response to determining an error has been detected in the first memory, access to the first memory via the first memory interface is inhibited. Also, the first memory interface is locally restarted without restarting the second memory interface.

Abstract: A data processing system includes a memory system, a plurality of masters that issue requests for access to memory blocks within the memory system, a plurality of snoopers that provide partial responses to requests by the masters, and response logic that generates combined responses for the requests in response to the partial responses provided by the plurality of snoopers. The plurality masters includes a winning master that issues a request for a particular memory block, and the plurality of snoopers includes a protecting snooper that, in response to receipt of the request, provides a partial response and protects a transfer of coherency ownership of the particular memory block to the winning master until expiration of a protection window extension following receipt from the response logic of a combined response for the request.

Abstract: A cache coherent data processing system includes a plurality of processing units each having at least an associated cache, a system memory, and a memory controller that is coupled to and controls access to the system memory. The system memory includes a plurality of storage locations for storing a memory block of data, where each of the plurality of storage locations is sized to store a sub-block of data. The system memory further includes metadata storage for storing metadata, such as a domain indicator, describing the memory block. In response to a failure of a storage location for a particular sub-block among the plurality of sub-blocks, the memory controller overwrites at least a portion of the metadata in the metadata storage with the particular sub-block of data.

Abstract: A data processing system includes a plurality of communication links and a plurality of processing units including a local master processing unit. The local master processing unit includes interconnect logic that couples the processing unit to one or more of the plurality of communication links and an originating master coupled to the interconnect logic. The originating master originates an operation by issuing a write-type request on at least one of the one or more communication links, receives from a snooper in the data processing system a destination tag identifying a route to the snooper, and, responsive to receipt of the combined response and the destination tag, initiates a data transfer including a data payload and a data tag identifying the route provided within the destination tag.

Abstract: A data processing system includes a plurality of processing units coupled for communication by a communication link and a configuration register. The configuration register has a plurality of different settings each corresponding to a respective one of a plurality of different link information allocations. Information is communicated over the communication link in accordance with a particular link information allocation among the plurality of link information allocations determined by a respective setting of the configuration register.

Abstract: A method, apparatus and computer instructions are provided to autonomically monitor and adjust system characteristics based on a customer optimization goal specified in a policy or profile. An autonomic management component is implemented in firmware comprising a set of control algorithms. Response to reading system characteristics from a plurality of sensors, the autononmic management component selects at least one control algorithm from the set and the control algorithm adjusts the parameters of the system characteristic to optimize performance according to the optimization goal specified by the customer.

Abstract: A cache memory logically partitions a cache array having a single access/command port into at least two slices, and uses a first cache directory to access the first cache array slice while using a second cache directory to access the second cache array slice, but accesses from the cache directories are managed using a single cache arbiter which controls the single access/command port. In the illustrative embodiment, each cache directory has its own directory arbiter to handle conflicting internal requests, and the directory arbiters communicate with the cache arbiter. An address tag associated with a load request is transmitted from the processor core with a designated bit that associates the address tag with only one of the cache array slices whose corresponding directory determines whether the address tag matches a currently valid cache entry.

Abstract: In a cache coherent data processing system including at least first and second coherency domains, a memory block is stored in a system memory in association with a domain indicator indicating whether or not the memory block is cached, if at all, only within the first coherency domain. A master in the first coherency domain determines whether or not a scope of broadcast transmission of an operation should extend beyond the first coherency domain by reference to the domain indicator stored in the cache and then performs a broadcast of the operation within the cache coherent data processing system in accordance with the determination.

Abstract: In a cache coherent data processing system including at least first and second coherency domains, a master performs a first broadcast of an operation within the cache coherent data processing system that is limited in scope of transmission to the first coherency domain. The master receives a response of the first coherency domain to the first broadcast of the operation. If the response indicates the operation cannot be serviced in the first coherency domain alone, the master increases the scope of transmission by performing a second broadcast of the operation in both the first and second coherency domains. If the response indicates the operation can be serviced in the first coherency domain, the master refrains from performing the second broadcast, so that communication bandwidth utilized to service the operation is reduced.

Abstract: A method and apparatus are provided for a support interface for memory-mapped resources. A support processor sends a sequence of commands over and FSI interface to a memory-mapped support interface on a processor chip. The memory-mapped support interface updates memory, memory-mapped registers or memory-mapped resources. The interface uses fabric packet generation logic to generate a single command packet in a protocol for the coherency fabric which consists of an address, command and/or data. Fabric commands are converted to FSI protocol and forwarded to attached support chips to access the memory-mapped resource, and responses from the support chips are converted back to fabric response packets. Fabric snoop logic monitors the coherency fabric and decodes responses for packets previously sent by fabric packet generation logic. The fabric snoop logic updates status register and/or writes response data to a read data register. The system also reports any errors that are encountered.

Abstract: In-band firmware executes instructions which cause commands to be sent on a coherency fabric. Fabric snoop logic monitors the coherency fabric for command packets that target a resource in one of the support chips attached via an FSI link. Conversion logic converts the information from the fabric packet into an FSI protocol. An FSI command is transmitted via the FSI transmit link to an FSI slave of the intended support chip. An FSI receive link receives response data from the FSI slave of the intended support chip. Conversion logic converts the information from the support chip received via the FSI receive link into the fabric protocol. Response packet generation logic generates the fabric response packet and returns it on the coherency fabric. An identical FSI link between a support processor and support chips allows direct access to the same resources on the support chips by out-of-band firmware.

Abstract: A cache coherent data processing system includes at least first and second coherency domains each including at least one processing unit and a cache memory. The cache memory includes a cache controller, a data array including a data storage location for caching a memory block, and a cache directory. The cache directory includes a tag field for storing an address tag in association with the memory block and a coherency state field associated with the tag field and the data storage location. The coherency state field has a plurality of possible states including a state that indicates that the address tag is valid, that the storage location does not contain valid data, and that the memory block is possibly cached outside of the first coherency domain.