摘要:
In an entry of a first cache memory within a first coherency domain of a data processing system including at least first and second coherency domains, a coherency state field is set to a first state that indicates that an associated address tag is valid, an associated storage location does not contain valid data, and a memory block identified by the address tag is likely cached outside the first coherency domain. In response to snooping a castout operation, the first cache memory determines if the castout operation hits in the entry and, if so, updates the coherency state field from the first state to a second state indicating that the associated address tag is invalid.
摘要:
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.
摘要:
According to a method of data processing, a predictor is maintained that indicates a historical scope of broadcast for one or more previous operations transmitted on an interconnect of a data processing system. A scope of broadcast of a subsequent operation is predictively selected by reference to the predictor.
摘要:
A data processing system includes a plurality of processing units, including at least a local master and a local hub, which are coupled for communication via a communication link. The local master includes a master capable of initiating an operation, a snooper capable of receiving an operation, and interconnect logic coupled to a communication link coupling the local master to the local hub. The interconnect logic includes request logic that synchronizes internal transmission of a request of the master to the snooper with transmission, via the communication link, of the request to the local hub.
摘要:
A data processing system includes a plurality of processing units, including at least a local master and a local hub, which are coupled for communication via a communication link. The local master includes a master capable of initiating an operation, a snooper capable of receiving an operation, and interconnect logic coupled to a communication link coupling the local master to the local hub. The interconnect logic includes request logic that synchronizes internal transmission of a request of the master to the snooper with transmission, via the communication link, of the request to the local hub.
摘要:
A data processing system includes a processor core having an associated upper level cache and a lower level victim cache. In response to a memory access request of the processor core that specifies a non-modifying access to a target coherency granule, a determination is made whether the memory access request hits or misses in a directory of the lower level victim cache. In response to determining that the memory access request hits in the lower level victim cache in a data-valid coherence state, the lower level victim cache provides the target coherency granule of the memory access request to the upper level cache. The lower level victim cache preserves the target coherency granule in the lower level victim cache in a shared coherence state if the memory access request is of a first type and invalidates the target coherency granule if the memory access request is of a second type.
摘要:
A data processing system includes at least a first through third processing nodes coupled by an interconnect fabric. The first processing node includes a master, a plurality of snoopers capable of participating in interconnect operations, and a node interface that receives a request of the master and transmits the request of the master to the second processing unit with a nodal scope of transmission limited to the second processing node. The second processing node includes a node interface having a directory. The node interface of the second processing node permits the request to proceed with the nodal scope of transmission if the directory does not indicate that a target memory block of the request is cached other than in the second processing node and prevents the request from succeeding if the directory indicates that the target memory block of the request is cached other than in the second processing node.
摘要:
A method and apparatus for preventing selection of Deleted (D) members as an LRU victim during LRU victim selection. During each cache access targeting the particular congruence class, the deleted cache line is identified from information in the cache directory. A location of a deleted cache line is pipelined through the cache architecture during LRU victim selection. The information is latched and then passed to MRU vector generation logic. An MRU vector is generated and passed to the MRU update logic, which is selects/tags the deleted member as a MRU member. The make MRU operation affects only the lower level LRU state bits arranged in a tree-based structure state bits so that the make MRU operation only negates selection of the specific member in the D state, without affecting LRU victim selection of the other members.
摘要:
A cache memory includes a cache array including a plurality of congruence classes each containing a plurality of cache lines, where each cache line belongs to one of multiple classes which include at least a first class and a second class. The cache memory also includes a cache directory of the cache array that indicates class membership. The cache memory further includes a cache controller that selects a victim cache line for eviction from a congruence class. If the congruence class contains a cache line belonging to the second class, the cache controller preferentially selects as the victim cache line a cache line of the congruence class belonging to the second class based upon access order. If the congruence class contains no cache line belonging to the second class, the cache controller selects as the victim cache line a cache line belonging to the first class based upon access order.
摘要:
A data processing system includes at least a first processing node having an input/output (I/O) controller and a second processing including a memory controller for a memory. The memory controller receives, in order, pipelined first and second DMA write operations from the I/O controller, where the first and second DMA write operations target first and second addresses, respectively. In response to the second DMA write operation, the memory controller establishes a state of a domain indicator associated with the second address to indicate an operation scope including the first processing node. In response to the memory controller receiving a data access request specifying the second address and having a scope excluding the first processing node, the memory controller forces the data access request to be reissued with a scope including the first processing node based upon the state of the domain indicator associated with the second address.