摘要:
A data processing system includes an interconnect fabric, a system memory coupled to the interconnect fabric and including a virtual barrier synchronization region allocated to storage of virtual barrier synchronization registers (VBSRs), and a plurality of processing units coupled to the interconnect fabric and operable to access the virtual barrier synchronization region. Each of the plurality of processing units includes a processor core and a cache memory including a cache controller and a cache array that caches VBSR lines from the virtual barrier synchronization region of the system memory. The cache controller of a first processing unit, responsive to a memory access request from its processor core that targets a first VBSR line, transfers responsibility for writing back to the virtual barrier synchronization region a second VBSR line contemporaneously held in the cache arrays of first, second and third processing units. The responsibility is transferred via an election held over the interconnect fabric.
摘要:
Scrubbing logic in a local coherency domain issues a domain query request to at least one cache hierarchy in a remote coherency domain. The domain query request is a non-destructive probe of a coherency state associated with a target memory block by the at least one cache hierarchy. A coherency response to the domain query request is received. In response to the coherency response indicating that the target memory block is not cached in the remote coherency domain, a domain indication in the local coherency domain is updated to indicate that the target memory block is cached, if at all, only within the local coherency domain.
摘要:
A data processing system includes a local processor core and a cache memory coupled to the local processor core. The cache memory includes a data array, a directory of contents of the data array, at least one snoop machine that services memory access requests of a remote processor core, and multiple state machines that service memory access requests of the local processor core. The multiple state machines include a first state machine that has a first set of memory access requests of the local processor core that it is capable of servicing and a second state machine that has a different second set of memory access requests of the local processor core that it is capable of servicing.
摘要:
A processing unit includes a local processor core and a cache memory coupled to the local processor core. The cache memory includes a data array, a directory of contents of the data array. The cache memory further includes one or more state machines that service a first set of memory access requests, an arbiter that directs servicing of a second set of memory access requests by reference to the data array and the directory on a fixed schedule, address collision logic that protects memory access requests in the second set by detecting and signaling address conflicts between active memory access requests in the second set and subsequent memory access requests, and dispatch logic coupled to the address collision logic. The dispatch logic dispatches memory access requests in the first set to the one or more state machines for servicing and signals the arbiter to direct servicing of memory access requests in the second set according to the fixed schedule.
摘要:
Fine-grained detection of data modification of original data is provided by associating separate guard bits with granules of memory storing original data from which translated data has been obtained. The guard bits indicating whether the original data stored in the associated granule is protected for data coherency. The guard bits are set and cleared by special-purpose instructions. Responsive to attempting access to translated data obtained from the original data, the guard bit(s) associated with the original data is checked to determine whether the guard bit(s) fail to indicate coherency of the original data, and if so, discarding of the translated data is initiated to facilitate maintaining data coherency between the original data and the translated data.
摘要:
A method is provided for fine-grained detection of data modification of original data by associating separate guard bits with granules of memory storing original data from which translated data has been obtained. The guard bits indicating whether the original data stored in the associated granule is protected for data coherency. The guard bits are set and cleared by special-purpose instructions. Responsive to attempting access to translated data obtained from the original data, the guard bit(s) associated with the original data is checked to determine whether the guard bit(s) fail to indicate coherency of the original data, and if so, discarding of the translated data is initiated to facilitate maintaining data coherency between the original data and the translated data.
摘要:
A store request in enqueued in a store queue of a cache memory of the data processing system. The store request identifies a target memory block by a target address and specifies store data. While the store request and a barrier request older than the store request are enqueued in the store queue, a read-claim machine of the cache memory is dispatched to acquire coherence ownership of target memory block of the store request. After coherence ownership of the target memory block is acquired and the barrier request has been retired from the store queue, a cache array of the cache memory is updated with the store data.
摘要:
A first SMP computer has first and second processing units and a first system memory pool, a second SMP computer has third and fourth processing units and a second system memory pool, and a third SMP computer has at least fifth and sixth processing units and third, fourth and fifth system memory pools. The fourth system memory pool is inaccessible to the third, fourth and sixth processing units and accessible to at least the second and fifth processing units, and the fifth system memory pool is inaccessible to the first, second and sixth processing units and accessible to at least the fourth and fifth processing units. A first interconnect couples the second processing unit for load-store coherent, ordered access to the fourth system memory pool, and a second interconnect couples the fourth processing unit for load-store coherent, ordered access to the fifth system memory pool.
摘要:
A data processing system includes first and second processing units and a system memory. The first processing unit has first upper and first lower level caches, and the second processing unit has second upper and lower level caches. In response to a data request, a victim cache line to be castout from the first lower level cache is selected, and the first lower level cache selects between performing a lateral castout (LCO) of the victim cache line to the second lower level cache and a castout of the victim cache line to the system memory based upon a confidence indicator associated with the victim cache line. In response to selecting an LCO, the first processing unit issues an LCO command on the interconnect fabric and removes the victim cache line from the first lower level cache, and the second lower level cache holds the victim cache line.
摘要:
In at least one embodiment, a method of data processing in a data processing system having a memory hierarchy includes a processor core executing a storage-modifying memory access instruction to determine a memory address. The processor core transmits to a cache memory within the memory hierarchy a storage-modifying memory access request including the memory address, an indication of a memory access type, and, if present, a partial cache line hint signaling access to less than all granules of a target cache line of data associated with the memory address. In response to the storage-modifying memory access request, the cache memory performs a storage-modifying access to all granules of the target cache line of data if the partial cache line hint is not present and performs a storage-modifying access to less than all granules of the target cache line of data if the partial cache line hint is present.